-This function frees the memory used for a compiled pattern, including any +If code is NULL, this function does nothing. Otherwise, code must +point to a compiled pattern. This function frees its memory, including any memory used by the JIT compiler. If the compiled pattern was created by a call to pcre2_code_copy_with_tables(), the memory for the character tables is also freed. diff --git a/doc/html/pcre2_compile_context_free.html b/doc/html/pcre2_compile_context_free.html index ea67a18..b4159b1 100644 --- a/doc/html/pcre2_compile_context_free.html +++ b/doc/html/pcre2_compile_context_free.html @@ -27,7 +27,8 @@ DESCRIPTION
This function frees the memory occupied by a compile context, using the memory freeing function from the general context with which it was created, or -free() if that was not set. +free() if that was not set. If the argument is NULL, the function returns +immediately without doing anything.
There is a complete description of the PCRE2 native API in the diff --git a/doc/html/pcre2_convert_context_free.html b/doc/html/pcre2_convert_context_free.html index ab6db6c..6ad9794 100644 --- a/doc/html/pcre2_convert_context_free.html +++ b/doc/html/pcre2_convert_context_free.html @@ -28,7 +28,8 @@ DESCRIPTION This function is part of an experimental set of pattern conversion functions. It frees the memory occupied by a convert context, using the memory freeing function from the general context with which it was created, or -free() if that was not set. +free() if that was not set. If the argument is NULL, the function returns +immediately without doing anything.
The pattern conversion functions are described in the diff --git a/doc/html/pcre2_converted_pattern_free.html b/doc/html/pcre2_converted_pattern_free.html index 11adefd..2133341 100644 --- a/doc/html/pcre2_converted_pattern_free.html +++ b/doc/html/pcre2_converted_pattern_free.html @@ -28,7 +28,8 @@ DESCRIPTION This function is part of an experimental set of pattern conversion functions. It frees the memory occupied by a converted pattern that was obtained by calling pcre2_pattern_convert() with arguments that caused it to place -the converted pattern into newly obtained heap memory. +the converted pattern into newly obtained heap memory. If the argument is NULL, +the function returns immediately without doing anything.
The pattern conversion functions are described in the
diff --git a/doc/html/pcre2_general_context_free.html b/doc/html/pcre2_general_context_free.html
index ec818ef..9f335f5 100644
--- a/doc/html/pcre2_general_context_free.html
+++ b/doc/html/pcre2_general_context_free.html
@@ -26,7 +26,8 @@ DESCRIPTION
This function frees the memory occupied by a general context, using the memory -freeing function within the context, if set. +freeing function within the context, if set. If the argument is NULL, the +function returns immediately without doing anything.
There is a complete description of the PCRE2 native API in the diff --git a/doc/html/pcre2_jit_stack_assign.html b/doc/html/pcre2_jit_stack_assign.html index 2c6898a..6730ba5 100644 --- a/doc/html/pcre2_jit_stack_assign.html +++ b/doc/html/pcre2_jit_stack_assign.html @@ -38,6 +38,10 @@ passed to a matching function. The arguments of this function are:
+If mcontext is NULL, the function returns immediately, without doing +anything. +
+If callback is NULL and callback_data is NULL, an internal 32KiB block on the machine stack is used.
diff --git a/doc/html/pcre2_jit_stack_free.html b/doc/html/pcre2_jit_stack_free.html index 21ac276..3ec5338 100644 --- a/doc/html/pcre2_jit_stack_free.html +++ b/doc/html/pcre2_jit_stack_free.html @@ -26,8 +26,9 @@ DESCRIPTIONThis function is used to free a JIT stack that was created by -pcre2_jit_stack_create() when it is no longer needed. For more details, -see the +pcre2_jit_stack_create() when it is no longer needed. If the argument is +NULL, the function returns immediately without doing anything. For more +details, see the pcre2jit page.
diff --git a/doc/html/pcre2_match_context_free.html b/doc/html/pcre2_match_context_free.html index 8248974..7f00ea9 100644 --- a/doc/html/pcre2_match_context_free.html +++ b/doc/html/pcre2_match_context_free.html @@ -27,7 +27,8 @@ DESCRIPTIONThis function frees the memory occupied by a match context, using the memory freeing function from the general context with which it was created, or -free() if that was not set. +free() if that was not set. If the argument is NULL, the function returns +immediately without doing anything.
There is a complete description of the PCRE2 native API in the
diff --git a/doc/html/pcre2_match_data_free.html b/doc/html/pcre2_match_data_free.html
index 840067f..68a4461 100644
--- a/doc/html/pcre2_match_data_free.html
+++ b/doc/html/pcre2_match_data_free.html
@@ -25,9 +25,10 @@ SYNOPSIS
DESCRIPTION
-This function frees the memory occupied by a match data block, using the memory -freeing function from the general context or compiled pattern with which it was -created, or free() if that was not set. +If match_data is NULL, this function does nothing. Otherwise, +match_data must point to a match data block, which this function frees, +using the memory freeing function from the general context or compiled pattern +with which it was created, or free() if that was not set.
There is a complete description of the PCRE2 native API in the diff --git a/doc/html/pcre2_serialize_free.html b/doc/html/pcre2_serialize_free.html index 9b3c464..b6e41c9 100644 --- a/doc/html/pcre2_serialize_free.html +++ b/doc/html/pcre2_serialize_free.html @@ -27,7 +27,8 @@ DESCRIPTION
This function frees the memory that was obtained by pcre2_serialize_encode() to hold a serialized byte stream. The argument -must point to such a byte stream. +must point to such a byte stream or be NULL, in which case the function returns +without doing anything.
There is a complete description of the PCRE2 native API in the diff --git a/doc/html/pcre2_substring_free.html b/doc/html/pcre2_substring_free.html index 35a5b55..e0d0fbd 100644 --- a/doc/html/pcre2_substring_free.html +++ b/doc/html/pcre2_substring_free.html @@ -28,7 +28,7 @@ DESCRIPTION This is a convenience function for freeing the memory obtained by a previous call to pcre2_substring_get_byname() or pcre2_substring_get_bynumber(). Its only argument is a pointer to the -string. +string. If the argument is NULL, the function does nothing.
There is a complete description of the PCRE2 native API in the diff --git a/doc/html/pcre2_substring_list_free.html b/doc/html/pcre2_substring_list_free.html index d61241d..922a139 100644 --- a/doc/html/pcre2_substring_list_free.html +++ b/doc/html/pcre2_substring_list_free.html @@ -27,7 +27,8 @@ DESCRIPTION
This is a convenience function for freeing the store obtained by a previous call to pcre2substring_list_get(). Its only argument is a pointer to -the list of string pointers. +the list of string pointers. If the argument is NULL, the function returns +immediately, without doing anything.
There is a complete description of the PCRE2 native API in the diff --git a/doc/html/pcre2api.html b/doc/html/pcre2api.html index 11f60b6..ddc60fc 100644 --- a/doc/html/pcre2api.html +++ b/doc/html/pcre2api.html @@ -518,7 +518,9 @@ been matched by pcre2_match(). They are: pcre2_substring_number_from_name() pcre2_substring_free() and pcre2_substring_list_free() are also -provided, to free memory used for extracted strings. +provided, to free memory used for extracted strings. If either of these +functions is called with a NULL argument, the function returns immediately +without doing anything.
The function pcre2_substitute() can be called to match a pattern and
@@ -727,6 +729,10 @@ The memory used for a general context should be freed by calling:
void pcre2_general_context_free(pcre2_general_context *gcontext);
+
+
+If this function is passed a NULL argument, it function returns immediately
+without doing anything.
The function pcre2_code_copy() makes a copy of the compiled code in new @@ -1257,7 +1265,8 @@ if the code has been processed by the JIT compiler (see below), the JIT information cannot be copied (because it is position-dependent). The new copy can initially be used only for non-JIT matching, though it can be -passed to pcre2_jit_compile() if required. +passed to pcre2_jit_compile() if required. If pcre2_code_copy() is +called with a NULL argument, it returns NULL.
The pcre2_code_copy() function provides a way for individual threads in a @@ -1272,7 +1281,9 @@ there are occasions when a copy of a compiled pattern and the relevant tables are needed. The pcre2_code_copy_with_tables() provides this facility. Copies of both the code and the tables are made, with the new code pointing to the new tables. The memory for the new tables is automatically freed when -pcre2_code_free() is called for the new copy of the compiled code. +pcre2_code_free() is called for the new copy of the compiled code. If +pcre2_code_copy_withy_tables() is called with a NULL argument, it returns +NULL.
NOTE: When one of the matching functions is called, pointers to the compiled @@ -2363,7 +2374,8 @@ match data block (for that match) have taken place.
When a match data block itself is no longer needed, it should be freed by -calling pcre2_match_data_free(). +calling pcre2_match_data_free(). If this function is called with a NULL +argument, it returns immediately, without doing anything.
@@ -3619,7 +3631,7 @@ Cambridge, England.
-Last updated: 22 June 2018
+Last updated: 28 June 2018
Copyright © 1997-2018 University of Cambridge.
diff --git a/doc/html/pcre2convert.html b/doc/html/pcre2convert.html
index 8b4d87f..7372e08 100644
--- a/doc/html/pcre2convert.html
+++ b/doc/html/pcre2convert.html
@@ -105,7 +105,8 @@ If buffer points to a NULL pointer, an output buffer is obtained using
the allocator in the context or malloc() if no context is supplied. A
pointer to this buffer is placed in the variable to which buffer points.
When no longer needed the output buffer must be freed by calling
-pcre2_converted_pattern_free().
+pcre2_converted_pattern_free(). If this function is called with a NULL
+argument, it returns immediately without doing anything.
If buffer points to a non-NULL pointer, blength must be set to the @@ -181,9 +182,9 @@ Cambridge, England.
-Last updated: 12 July 2017
+Last updated: 28 June 2018
-Copyright © 1997-2017 University of Cambridge.
+Copyright © 1997-2018 University of Cambridge.
Return to the PCRE2 index page. diff --git a/doc/html/pcre2jit.html b/doc/html/pcre2jit.html index 6d2683d..330e993 100644 --- a/doc/html/pcre2jit.html +++ b/doc/html/pcre2jit.html @@ -193,9 +193,10 @@ are a starting size, a maximum size, and a general context (for memory allocation functions, or NULL for standard memory allocation). It returns a pointer to an opaque structure of type pcre2_jit_stack, or NULL if there is an error. The pcre2_jit_stack_free() function is used to free a stack -that is no longer needed. (For the technically minded: the address space is -allocated by mmap or VirtualAlloc.) A maximum stack size of 512KiB to 1MiB -should be more than enough for any pattern. +that is no longer needed. If its argument is NULL, this function returns +immediately, without doing anything. (For the technically minded: the address +space is allocated by mmap or VirtualAlloc.) A maximum stack size of 512KiB to +1MiB should be more than enough for any pattern.
The pcre2_jit_stack_assign() function specifies which stack JIT code @@ -207,7 +208,8 @@ should use. Its arguments are as follows: The first argument is a pointer to a match context. When this is subsequently passed to a matching function, its information determines which JIT stack is -used. There are three cases for the values of the other two options: +used. If this argument is NULL, the function returns immediately, without doing +anything. There are three cases for the values of the other two options:
(1) If callback is NULL and data is NULL, an internal 32KiB block
on the machine stack is used. This is the default when a match
@@ -432,9 +434,9 @@ Cambridge, England.
REVISION
-Last updated: 31 March 2017
+Last updated: 28 June 2018
-Copyright © 1997-2017 University of Cambridge.
+Copyright © 1997-2018 University of Cambridge.
Return to the PCRE2 index page.
diff --git a/doc/html/pcre2serialize.html b/doc/html/pcre2serialize.html
index 3336e04..0a7669e 100644
--- a/doc/html/pcre2serialize.html
+++ b/doc/html/pcre2serialize.html
@@ -129,7 +129,9 @@ non-binary data, be sure that the file is opened for binary output.
Serializing a set of patterns leaves the original data untouched, so they can
still be used for matching. Their memory must eventually be freed in the usual
way by calling pcre2_code_free(). When you have finished with the byte
-stream, it too must be freed by calling pcre2_serialize_free().
+stream, it too must be freed by calling pcre2_serialize_free(). If this
+function is called with a NULL argument, it returns immediately without doing
+anything.
RE-USING PRECOMPILED PATTERNS
diff --git a/doc/pcre2.txt b/doc/pcre2.txt
index 5453f47..4b06670 100644
--- a/doc/pcre2.txt
+++ b/doc/pcre2.txt
@@ -578,7 +578,9 @@ PCRE2 API OVERVIEW
pcre2_substring_number_from_name()
pcre2_substring_free() and pcre2_substring_list_free() are also pro-
- vided, to free memory used for extracted strings.
+ vided, to free memory used for extracted strings. If either of these
+ functions is called with a NULL argument, the function returns immedi-
+ ately without doing anything.
The function pcre2_substitute() can be called to match a pattern and
return a copy of the subject string with substitutions for parts that
@@ -772,11 +774,13 @@ PCRE2 CONTEXTS
void pcre2_general_context_free(pcre2_general_context *gcontext);
+ If this function is passed a NULL argument, it function returns immedi-
+ ately without doing anything.
The compile context
- A compile context is required if you want to provide an external func-
- tion for stack checking during compilation or to change the default
+ A compile context is required if you want to provide an external func-
+ tion for stack checking during compilation or to change the default
values of any of the following compile-time parameters:
What \R matches (Unicode newlines or CR, LF, CRLF only)
@@ -786,11 +790,11 @@ PCRE2 CONTEXTS
The maximum length of the pattern string
The extra options bits (none set by default)
- A compile context is also required if you are using custom memory man-
- agement. If none of these apply, just pass NULL as the context argu-
+ A compile context is also required if you are using custom memory man-
+ agement. If none of these apply, just pass NULL as the context argu-
ment of pcre2_compile().
- A compile context is created, copied, and freed by the following func-
+ A compile context is created, copied, and freed by the following func-
tions:
pcre2_compile_context *pcre2_compile_context_create(
@@ -801,91 +805,91 @@ PCRE2 CONTEXTS
void pcre2_compile_context_free(pcre2_compile_context *ccontext);
- A compile context is created with default values for its parameters.
+ A compile context is created with default values for its parameters.
These can be changed by calling the following functions, which return 0
on success, or PCRE2_ERROR_BADDATA if invalid data is detected.
int pcre2_set_bsr(pcre2_compile_context *ccontext,
uint32_t value);
- The value must be PCRE2_BSR_ANYCRLF, to specify that \R matches only
- CR, LF, or CRLF, or PCRE2_BSR_UNICODE, to specify that \R matches any
+ The value must be PCRE2_BSR_ANYCRLF, to specify that \R matches only
+ CR, LF, or CRLF, or PCRE2_BSR_UNICODE, to specify that \R matches any
Unicode line ending sequence. The value is used by the JIT compiler and
- by the two interpreted matching functions, pcre2_match() and
+ by the two interpreted matching functions, pcre2_match() and
pcre2_dfa_match().
int pcre2_set_character_tables(pcre2_compile_context *ccontext,
const unsigned char *tables);
- The value must be the result of a call to pcre2_maketables(), whose
+ The value must be the result of a call to pcre2_maketables(), whose
only argument is a general context. This function builds a set of char-
acter tables in the current locale.
int pcre2_set_compile_extra_options(pcre2_compile_context *ccontext,
uint32_t extra_options);
- As PCRE2 has developed, almost all the 32 option bits that are avail-
- able in the options argument of pcre2_compile() have been used up. To
- avoid running out, the compile context contains a set of extra option
- bits which are used for some newer, assumed rarer, options. This func-
- tion sets those bits. It always sets all the bits (either on or off).
- It does not modify any existing setting. The available options are
+ As PCRE2 has developed, almost all the 32 option bits that are avail-
+ able in the options argument of pcre2_compile() have been used up. To
+ avoid running out, the compile context contains a set of extra option
+ bits which are used for some newer, assumed rarer, options. This func-
+ tion sets those bits. It always sets all the bits (either on or off).
+ It does not modify any existing setting. The available options are
defined in the section entitled "Extra compile options" below.
int pcre2_set_max_pattern_length(pcre2_compile_context *ccontext,
PCRE2_SIZE value);
- This sets a maximum length, in code units, for any pattern string that
- is compiled with this context. If the pattern is longer, an error is
- generated. This facility is provided so that applications that accept
+ This sets a maximum length, in code units, for any pattern string that
+ is compiled with this context. If the pattern is longer, an error is
+ generated. This facility is provided so that applications that accept
patterns from external sources can limit their size. The default is the
- largest number that a PCRE2_SIZE variable can hold, which is effec-
+ largest number that a PCRE2_SIZE variable can hold, which is effec-
tively unlimited.
int pcre2_set_newline(pcre2_compile_context *ccontext,
uint32_t value);
This specifies which characters or character sequences are to be recog-
- nized as newlines. The value must be one of PCRE2_NEWLINE_CR (carriage
+ nized as newlines. The value must be one of PCRE2_NEWLINE_CR (carriage
return only), PCRE2_NEWLINE_LF (linefeed only), PCRE2_NEWLINE_CRLF (the
- two-character sequence CR followed by LF), PCRE2_NEWLINE_ANYCRLF (any
- of the above), PCRE2_NEWLINE_ANY (any Unicode newline sequence), or
+ two-character sequence CR followed by LF), PCRE2_NEWLINE_ANYCRLF (any
+ of the above), PCRE2_NEWLINE_ANY (any Unicode newline sequence), or
PCRE2_NEWLINE_NUL (the NUL character, that is a binary zero).
A pattern can override the value set in the compile context by starting
with a sequence such as (*CRLF). See the pcre2pattern page for details.
- When a pattern is compiled with the PCRE2_EXTENDED or
+ When a pattern is compiled with the PCRE2_EXTENDED or
PCRE2_EXTENDED_MORE option, the newline convention affects the recogni-
- tion of white space and the end of internal comments starting with #.
- The value is saved with the compiled pattern for subsequent use by the
- JIT compiler and by the two interpreted matching functions,
+ tion of white space and the end of internal comments starting with #.
+ The value is saved with the compiled pattern for subsequent use by the
+ JIT compiler and by the two interpreted matching functions,
pcre2_match() and pcre2_dfa_match().
int pcre2_set_parens_nest_limit(pcre2_compile_context *ccontext,
uint32_t value);
This parameter ajusts the limit, set when PCRE2 is built (default 250),
- on the depth of parenthesis nesting in a pattern. This limit stops
- rogue patterns using up too much system stack when being compiled. The
+ on the depth of parenthesis nesting in a pattern. This limit stops
+ rogue patterns using up too much system stack when being compiled. The
limit applies to parentheses of all kinds, not just capturing parenthe-
ses.
int pcre2_set_compile_recursion_guard(pcre2_compile_context *ccontext,
int (*guard_function)(uint32_t, void *), void *user_data);
- There is at least one application that runs PCRE2 in threads with very
- limited system stack, where running out of stack is to be avoided at
- all costs. The parenthesis limit above cannot take account of how much
- stack is actually available during compilation. For a finer control,
- you can supply a function that is called whenever pcre2_compile()
- starts to compile a parenthesized part of a pattern. This function can
- check the actual stack size (or anything else that it wants to, of
+ There is at least one application that runs PCRE2 in threads with very
+ limited system stack, where running out of stack is to be avoided at
+ all costs. The parenthesis limit above cannot take account of how much
+ stack is actually available during compilation. For a finer control,
+ you can supply a function that is called whenever pcre2_compile()
+ starts to compile a parenthesized part of a pattern. This function can
+ check the actual stack size (or anything else that it wants to, of
course).
- The first argument to the callout function gives the current depth of
- nesting, and the second is user data that is set up by the last argu-
- ment of pcre2_set_compile_recursion_guard(). The callout function
+ The first argument to the callout function gives the current depth of
+ nesting, and the second is user data that is set up by the last argu-
+ ment of pcre2_set_compile_recursion_guard(). The callout function
should return zero if all is well, or non-zero to force an error.
The match context
@@ -899,10 +903,10 @@ PCRE2 CONTEXTS
Change the backtracking depth limit
Set custom memory management specifically for the match
- If none of these apply, just pass NULL as the context argument of
+ If none of these apply, just pass NULL as the context argument of
pcre2_match(), pcre2_dfa_match(), or pcre2_jit_match().
- A match context is created, copied, and freed by the following func-
+ A match context is created, copied, and freed by the following func-
tions:
pcre2_match_context *pcre2_match_context_create(
@@ -913,7 +917,7 @@ PCRE2 CONTEXTS
void pcre2_match_context_free(pcre2_match_context *mcontext);
- A match context is created with default values for its parameters.
+ A match context is created with default values for its parameters.
These can be changed by calling the following functions, which return 0
on success, or PCRE2_ERROR_BADDATA if invalid data is detected.
@@ -928,29 +932,29 @@ PCRE2 CONTEXTS
int pcre2_set_offset_limit(pcre2_match_context *mcontext,
PCRE2_SIZE value);
- The offset_limit parameter limits how far an unanchored search can
- advance in the subject string. The default value is PCRE2_UNSET. The
- pcre2_match() and pcre2_dfa_match() functions return
- PCRE2_ERROR_NOMATCH if a match with a starting point before or at the
- given offset is not found. The pcre2_substitute() function makes no
+ The offset_limit parameter limits how far an unanchored search can
+ advance in the subject string. The default value is PCRE2_UNSET. The
+ pcre2_match() and pcre2_dfa_match() functions return
+ PCRE2_ERROR_NOMATCH if a match with a starting point before or at the
+ given offset is not found. The pcre2_substitute() function makes no
more substitutions.
- For example, if the pattern /abc/ is matched against "123abc" with an
- offset limit less than 3, the result is PCRE2_ERROR_NO_MATCH. A match
- can never be found if the startoffset argument of pcre2_match(),
- pcre2_dfa_match(), or pcre2_substitute() is greater than the offset
+ For example, if the pattern /abc/ is matched against "123abc" with an
+ offset limit less than 3, the result is PCRE2_ERROR_NO_MATCH. A match
+ can never be found if the startoffset argument of pcre2_match(),
+ pcre2_dfa_match(), or pcre2_substitute() is greater than the offset
limit set in the match context.
- When using this facility, you must set the PCRE2_USE_OFFSET_LIMIT
+ When using this facility, you must set the PCRE2_USE_OFFSET_LIMIT
option when calling pcre2_compile() so that when JIT is in use, differ-
- ent code can be compiled. If a match is started with a non-default
- match limit when PCRE2_USE_OFFSET_LIMIT is not set, an error is gener-
+ ent code can be compiled. If a match is started with a non-default
+ match limit when PCRE2_USE_OFFSET_LIMIT is not set, an error is gener-
ated.
- The offset limit facility can be used to track progress when searching
- large subject strings or to limit the extent of global substitutions.
- See also the PCRE2_FIRSTLINE option, which requires a match to start
- before or at the first newline that follows the start of matching in
+ The offset limit facility can be used to track progress when searching
+ large subject strings or to limit the extent of global substitutions.
+ See also the PCRE2_FIRSTLINE option, which requires a match to start
+ before or at the first newline that follows the start of matching in
the subject. If this is set with an offset limit, a match must occur in
the first line and also within the offset limit. In other words, which-
ever limit comes first is used.
@@ -959,15 +963,15 @@ PCRE2 CONTEXTS
uint32_t value);
The heap_limit parameter specifies, in units of kibibytes (1024 bytes),
- the maximum amount of heap memory that pcre2_match() may use to hold
+ the maximum amount of heap memory that pcre2_match() may use to hold
backtracking information when running an interpretive match. This limit
also applies to pcre2_dfa_match(), which may use the heap when process-
- ing patterns with a lot of nested pattern recursion or lookarounds or
+ ing patterns with a lot of nested pattern recursion or lookarounds or
atomic groups. This limit does not apply to matching with the JIT opti-
- mization, which has its own memory control arrangements (see the
- pcre2jit documentation for more details). If the limit is reached, the
- negative error code PCRE2_ERROR_HEAPLIMIT is returned. The default
- limit can be set when PCRE2 is built; if it is not, the default is set
+ mization, which has its own memory control arrangements (see the
+ pcre2jit documentation for more details). If the limit is reached, the
+ negative error code PCRE2_ERROR_HEAPLIMIT is returned. The default
+ limit can be set when PCRE2 is built; if it is not, the default is set
very large and is essentially "unlimited".
A value for the heap limit may also be supplied by an item at the start
@@ -975,100 +979,100 @@ PCRE2 CONTEXTS
(*LIMIT_HEAP=ddd)
- where ddd is a decimal number. However, such a setting is ignored
- unless ddd is less than the limit set by the caller of pcre2_match()
+ where ddd is a decimal number. However, such a setting is ignored
+ unless ddd is less than the limit set by the caller of pcre2_match()
or, if no such limit is set, less than the default.
- The pcre2_match() function starts out using a 20KiB vector on the sys-
+ The pcre2_match() function starts out using a 20KiB vector on the sys-
tem stack for recording backtracking points. The more nested backtrack-
- ing points there are (that is, the deeper the search tree), the more
- memory is needed. Heap memory is used only if the initial vector is
+ ing points there are (that is, the deeper the search tree), the more
+ memory is needed. Heap memory is used only if the initial vector is
too small. If the heap limit is set to a value less than 21 (in partic-
- ular, zero) no heap memory will be used. In this case, only patterns
- that do not have a lot of nested backtracking can be successfully pro-
+ ular, zero) no heap memory will be used. In this case, only patterns
+ that do not have a lot of nested backtracking can be successfully pro-
cessed.
- Similarly, for pcre2_dfa_match(), a vector on the system stack is used
- when processing pattern recursions, lookarounds, or atomic groups, and
- only if this is not big enough is heap memory used. In this case, too,
+ Similarly, for pcre2_dfa_match(), a vector on the system stack is used
+ when processing pattern recursions, lookarounds, or atomic groups, and
+ only if this is not big enough is heap memory used. In this case, too,
setting a value of zero disables the use of the heap.
int pcre2_set_match_limit(pcre2_match_context *mcontext,
uint32_t value);
- The match_limit parameter provides a means of preventing PCRE2 from
+ The match_limit parameter provides a means of preventing PCRE2 from
using up too many computing resources when processing patterns that are
not going to match, but which have a very large number of possibilities
- in their search trees. The classic example is a pattern that uses
+ in their search trees. The classic example is a pattern that uses
nested unlimited repeats.
- There is an internal counter in pcre2_match() that is incremented each
- time round its main matching loop. If this value reaches the match
+ There is an internal counter in pcre2_match() that is incremented each
+ time round its main matching loop. If this value reaches the match
limit, pcre2_match() returns the negative value PCRE2_ERROR_MATCHLIMIT.
- This has the effect of limiting the amount of backtracking that can
+ This has the effect of limiting the amount of backtracking that can
take place. For patterns that are not anchored, the count restarts from
- zero for each position in the subject string. This limit also applies
+ zero for each position in the subject string. This limit also applies
to pcre2_dfa_match(), though the counting is done in a different way.
- When pcre2_match() is called with a pattern that was successfully pro-
+ When pcre2_match() is called with a pattern that was successfully pro-
cessed by pcre2_jit_compile(), the way in which matching is executed is
- entirely different. However, there is still the possibility of runaway
- matching that goes on for a very long time, and so the match_limit
- value is also used in this case (but in a different way) to limit how
+ entirely different. However, there is still the possibility of runaway
+ matching that goes on for a very long time, and so the match_limit
+ value is also used in this case (but in a different way) to limit how
long the matching can continue.
- The default value for the limit can be set when PCRE2 is built; the
- default default is 10 million, which handles all but the most extreme
- cases. A value for the match limit may also be supplied by an item at
+ The default value for the limit can be set when PCRE2 is built; the
+ default default is 10 million, which handles all but the most extreme
+ cases. A value for the match limit may also be supplied by an item at
the start of a pattern of the form
(*LIMIT_MATCH=ddd)
- where ddd is a decimal number. However, such a setting is ignored
+ where ddd is a decimal number. However, such a setting is ignored
unless ddd is less than the limit set by the caller of pcre2_match() or
pcre2_dfa_match() or, if no such limit is set, less than the default.
int pcre2_set_depth_limit(pcre2_match_context *mcontext,
uint32_t value);
- This parameter limits the depth of nested backtracking in
- pcre2_match(). Each time a nested backtracking point is passed, a new
+ This parameter limits the depth of nested backtracking in
+ pcre2_match(). Each time a nested backtracking point is passed, a new
memory "frame" is used to remember the state of matching at that point.
- Thus, this parameter indirectly limits the amount of memory that is
- used in a match. However, because the size of each memory "frame"
+ Thus, this parameter indirectly limits the amount of memory that is
+ used in a match. However, because the size of each memory "frame"
depends on the number of capturing parentheses, the actual memory limit
- varies from pattern to pattern. This limit was more useful in versions
+ varies from pattern to pattern. This limit was more useful in versions
before 10.30, where function recursion was used for backtracking.
- The depth limit is not relevant, and is ignored, when matching is done
+ The depth limit is not relevant, and is ignored, when matching is done
using JIT compiled code. However, it is supported by pcre2_dfa_match(),
- which uses it to limit the depth of nested internal recursive function
- calls that implement atomic groups, lookaround assertions, and pattern
+ which uses it to limit the depth of nested internal recursive function
+ calls that implement atomic groups, lookaround assertions, and pattern
recursions. This limits, indirectly, the amount of system stack that is
- used. It was more useful in versions before 10.32, when stack memory
+ used. It was more useful in versions before 10.32, when stack memory
was used for local workspace vectors for recursive function calls. From
- version 10.32, only local variables are allocated on the stack and as
+ version 10.32, only local variables are allocated on the stack and as
each call uses only a few hundred bytes, even a small stack can support
quite a lot of recursion.
- If the depth of internal recursive function calls is great enough,
- local workspace vectors are allocated on the heap from version 10.32
- onwards, so the depth limit also indirectly limits the amount of heap
+ If the depth of internal recursive function calls is great enough,
+ local workspace vectors are allocated on the heap from version 10.32
+ onwards, so the depth limit also indirectly limits the amount of heap
memory that is used. A recursive pattern such as /(.(?2))((?1)|)/, when
- matched to a very long string using pcre2_dfa_match(), can use a great
- deal of memory. However, it is probably better to limit heap usage
+ matched to a very long string using pcre2_dfa_match(), can use a great
+ deal of memory. However, it is probably better to limit heap usage
directly by calling pcre2_set_heap_limit().
- The default value for the depth limit can be set when PCRE2 is built;
- if it is not, the default is set to the same value as the default for
- the match limit. If the limit is exceeded, pcre2_match() or
+ The default value for the depth limit can be set when PCRE2 is built;
+ if it is not, the default is set to the same value as the default for
+ the match limit. If the limit is exceeded, pcre2_match() or
pcre2_dfa_match() returns PCRE2_ERROR_DEPTHLIMIT. A value for the depth
- limit may also be supplied by an item at the start of a pattern of the
+ limit may also be supplied by an item at the start of a pattern of the
form
(*LIMIT_DEPTH=ddd)
- where ddd is a decimal number. However, such a setting is ignored
+ where ddd is a decimal number. However, such a setting is ignored
unless ddd is less than the limit set by the caller of pcre2_match() or
pcre2_dfa_match() or, if no such limit is set, less than the default.
@@ -1077,96 +1081,96 @@ CHECKING BUILD-TIME OPTIONS
int pcre2_config(uint32_t what, void *where);
- The function pcre2_config() makes it possible for a PCRE2 client to
- discover which optional features have been compiled into the PCRE2
- library. The pcre2build documentation has more details about these
+ The function pcre2_config() makes it possible for a PCRE2 client to
+ discover which optional features have been compiled into the PCRE2
+ library. The pcre2build documentation has more details about these
optional features.
- The first argument for pcre2_config() specifies which information is
- required. The second argument is a pointer to memory into which the
- information is placed. If NULL is passed, the function returns the
- amount of memory that is needed for the requested information. For
- calls that return numerical values, the value is in bytes; when
- requesting these values, where should point to appropriately aligned
- memory. For calls that return strings, the required length is given in
+ The first argument for pcre2_config() specifies which information is
+ required. The second argument is a pointer to memory into which the
+ information is placed. If NULL is passed, the function returns the
+ amount of memory that is needed for the requested information. For
+ calls that return numerical values, the value is in bytes; when
+ requesting these values, where should point to appropriately aligned
+ memory. For calls that return strings, the required length is given in
code units, not counting the terminating zero.
- When requesting information, the returned value from pcre2_config() is
- non-negative on success, or the negative error code PCRE2_ERROR_BADOP-
- TION if the value in the first argument is not recognized. The follow-
+ When requesting information, the returned value from pcre2_config() is
+ non-negative on success, or the negative error code PCRE2_ERROR_BADOP-
+ TION if the value in the first argument is not recognized. The follow-
ing information is available:
PCRE2_CONFIG_BSR
- The output is a uint32_t integer whose value indicates what character
- sequences the \R escape sequence matches by default. A value of
+ The output is a uint32_t integer whose value indicates what character
+ sequences the \R escape sequence matches by default. A value of
PCRE2_BSR_UNICODE means that \R matches any Unicode line ending
- sequence; a value of PCRE2_BSR_ANYCRLF means that \R matches only CR,
+ sequence; a value of PCRE2_BSR_ANYCRLF means that \R matches only CR,
LF, or CRLF. The default can be overridden when a pattern is compiled.
PCRE2_CONFIG_COMPILED_WIDTHS
- The output is a uint32_t integer whose lower bits indicate which code
- unit widths were selected when PCRE2 was built. The 1-bit indicates
- 8-bit support, and the 2-bit and 4-bit indicate 16-bit and 32-bit sup-
+ The output is a uint32_t integer whose lower bits indicate which code
+ unit widths were selected when PCRE2 was built. The 1-bit indicates
+ 8-bit support, and the 2-bit and 4-bit indicate 16-bit and 32-bit sup-
port, respectively.
PCRE2_CONFIG_DEPTHLIMIT
- The output is a uint32_t integer that gives the default limit for the
- depth of nested backtracking in pcre2_match() or the depth of nested
- recursions, lookarounds, and atomic groups in pcre2_dfa_match(). Fur-
+ The output is a uint32_t integer that gives the default limit for the
+ depth of nested backtracking in pcre2_match() or the depth of nested
+ recursions, lookarounds, and atomic groups in pcre2_dfa_match(). Fur-
ther details are given with pcre2_set_depth_limit() above.
PCRE2_CONFIG_HEAPLIMIT
- The output is a uint32_t integer that gives, in kibibytes, the default
- limit for the amount of heap memory used by pcre2_match() or
- pcre2_dfa_match(). Further details are given with
+ The output is a uint32_t integer that gives, in kibibytes, the default
+ limit for the amount of heap memory used by pcre2_match() or
+ pcre2_dfa_match(). Further details are given with
pcre2_set_heap_limit() above.
PCRE2_CONFIG_JIT
- The output is a uint32_t integer that is set to one if support for
+ The output is a uint32_t integer that is set to one if support for
just-in-time compiling is available; otherwise it is set to zero.
PCRE2_CONFIG_JITTARGET
- The where argument should point to a buffer that is at least 48 code
- units long. (The exact length required can be found by calling
- pcre2_config() with where set to NULL.) The buffer is filled with a
- string that contains the name of the architecture for which the JIT
- compiler is configured, for example "x86 32bit (little endian +
- unaligned)". If JIT support is not available, PCRE2_ERROR_BADOPTION is
- returned, otherwise the number of code units used is returned. This is
+ The where argument should point to a buffer that is at least 48 code
+ units long. (The exact length required can be found by calling
+ pcre2_config() with where set to NULL.) The buffer is filled with a
+ string that contains the name of the architecture for which the JIT
+ compiler is configured, for example "x86 32bit (little endian +
+ unaligned)". If JIT support is not available, PCRE2_ERROR_BADOPTION is
+ returned, otherwise the number of code units used is returned. This is
the length of the string, plus one unit for the terminating zero.
PCRE2_CONFIG_LINKSIZE
The output is a uint32_t integer that contains the number of bytes used
- for internal linkage in compiled regular expressions. When PCRE2 is
- configured, the value can be set to 2, 3, or 4, with the default being
- 2. This is the value that is returned by pcre2_config(). However, when
- the 16-bit library is compiled, a value of 3 is rounded up to 4, and
- when the 32-bit library is compiled, internal linkages always use 4
+ for internal linkage in compiled regular expressions. When PCRE2 is
+ configured, the value can be set to 2, 3, or 4, with the default being
+ 2. This is the value that is returned by pcre2_config(). However, when
+ the 16-bit library is compiled, a value of 3 is rounded up to 4, and
+ when the 32-bit library is compiled, internal linkages always use 4
bytes, so the configured value is not relevant.
The default value of 2 for the 8-bit and 16-bit libraries is sufficient
- for all but the most massive patterns, since it allows the size of the
- compiled pattern to be up to 65535 code units. Larger values allow
- larger regular expressions to be compiled by those two libraries, but
+ for all but the most massive patterns, since it allows the size of the
+ compiled pattern to be up to 65535 code units. Larger values allow
+ larger regular expressions to be compiled by those two libraries, but
at the expense of slower matching.
PCRE2_CONFIG_MATCHLIMIT
The output is a uint32_t integer that gives the default match limit for
- pcre2_match(). Further details are given with pcre2_set_match_limit()
+ pcre2_match(). Further details are given with pcre2_set_match_limit()
above.
PCRE2_CONFIG_NEWLINE
- The output is a uint32_t integer whose value specifies the default
- character sequence that is recognized as meaning "newline". The values
+ The output is a uint32_t integer whose value specifies the default
+ character sequence that is recognized as meaning "newline". The values
are:
PCRE2_NEWLINE_CR Carriage return (CR)
@@ -1176,23 +1180,23 @@ CHECKING BUILD-TIME OPTIONS
PCRE2_NEWLINE_ANYCRLF Any of CR, LF, or CRLF
PCRE2_NEWLINE_NUL The NUL character (binary zero)
- The default should normally correspond to the standard sequence for
+ The default should normally correspond to the standard sequence for
your operating system.
PCRE2_CONFIG_NEVER_BACKSLASH_C
- The output is a uint32_t integer that is set to one if the use of \C
- was permanently disabled when PCRE2 was built; otherwise it is set to
+ The output is a uint32_t integer that is set to one if the use of \C
+ was permanently disabled when PCRE2 was built; otherwise it is set to
zero.
PCRE2_CONFIG_PARENSLIMIT
- The output is a uint32_t integer that gives the maximum depth of nest-
+ The output is a uint32_t integer that gives the maximum depth of nest-
ing of parentheses (of any kind) in a pattern. This limit is imposed to
- cap the amount of system stack used when a pattern is compiled. It is
- specified when PCRE2 is built; the default is 250. This limit does not
- take into account the stack that may already be used by the calling
- application. For finer control over compilation stack usage, see
+ cap the amount of system stack used when a pattern is compiled. It is
+ specified when PCRE2 is built; the default is 250. This limit does not
+ take into account the stack that may already be used by the calling
+ application. For finer control over compilation stack usage, see
pcre2_set_compile_recursion_guard().
PCRE2_CONFIG_STACKRECURSE
@@ -1202,25 +1206,25 @@ CHECKING BUILD-TIME OPTIONS
PCRE2_CONFIG_UNICODE_VERSION
- The where argument should point to a buffer that is at least 24 code
- units long. (The exact length required can be found by calling
- pcre2_config() with where set to NULL.) If PCRE2 has been compiled
- without Unicode support, the buffer is filled with the text "Unicode
- not supported". Otherwise, the Unicode version string (for example,
- "8.0.0") is inserted. The number of code units used is returned. This
+ The where argument should point to a buffer that is at least 24 code
+ units long. (The exact length required can be found by calling
+ pcre2_config() with where set to NULL.) If PCRE2 has been compiled
+ without Unicode support, the buffer is filled with the text "Unicode
+ not supported". Otherwise, the Unicode version string (for example,
+ "8.0.0") is inserted. The number of code units used is returned. This
is the length of the string plus one unit for the terminating zero.
PCRE2_CONFIG_UNICODE
- The output is a uint32_t integer that is set to one if Unicode support
- is available; otherwise it is set to zero. Unicode support implies UTF
+ The output is a uint32_t integer that is set to one if Unicode support
+ is available; otherwise it is set to zero. Unicode support implies UTF
support.
PCRE2_CONFIG_VERSION
- The where argument should point to a buffer that is at least 24 code
- units long. (The exact length required can be found by calling
- pcre2_config() with where set to NULL.) The buffer is filled with the
+ The where argument should point to a buffer that is at least 24 code
+ units long. (The exact length required can be found by calling
+ pcre2_config() with where set to NULL.) The buffer is filled with the
PCRE2 version string, zero-terminated. The number of code units used is
returned. This is the length of the string plus one unit for the termi-
nating zero.
@@ -1238,39 +1242,42 @@ COMPILING A PATTERN
pcre2_code *pcre2_code_copy_with_tables(const pcre2_code *code);
- The pcre2_compile() function compiles a pattern into an internal form.
- The pattern is defined by a pointer to a string of code units and a
- length (in code units). If the pattern is zero-terminated, the length
- can be specified as PCRE2_ZERO_TERMINATED. The function returns a
- pointer to a block of memory that contains the compiled pattern and
+ The pcre2_compile() function compiles a pattern into an internal form.
+ The pattern is defined by a pointer to a string of code units and a
+ length (in code units). If the pattern is zero-terminated, the length
+ can be specified as PCRE2_ZERO_TERMINATED. The function returns a
+ pointer to a block of memory that contains the compiled pattern and
related data, or NULL if an error occurred.
- If the compile context argument ccontext is NULL, memory for the com-
- piled pattern is obtained by calling malloc(). Otherwise, it is
- obtained from the same memory function that was used for the compile
- context. The caller must free the memory by calling pcre2_code_free()
- when it is no longer needed.
+ If the compile context argument ccontext is NULL, memory for the com-
+ piled pattern is obtained by calling malloc(). Otherwise, it is
+ obtained from the same memory function that was used for the compile
+ context. The caller must free the memory by calling pcre2_code_free()
+ when it is no longer needed. If pcre2_code_free() is called with a
+ NULL argument, it returns immediately, without doing anything.
The function pcre2_code_copy() makes a copy of the compiled code in new
memory, using the same memory allocator as was used for the original.
However, if the code has been processed by the JIT compiler (see
below), the JIT information cannot be copied (because it is position-
dependent). The new copy can initially be used only for non-JIT match-
- ing, though it can be passed to pcre2_jit_compile() if required.
+ ing, though it can be passed to pcre2_jit_compile() if required. If
+ pcre2_code_copy() is called with a NULL argument, it returns NULL.
The pcre2_code_copy() function provides a way for individual threads in
- a multithreaded application to acquire a private copy of shared com-
- piled code. However, it does not make a copy of the character tables
- used by the compiled pattern; the new pattern code points to the same
- tables as the original code. (See "Locale Support" below for details
- of these character tables.) In many applications the same tables are
- used throughout, so this behaviour is appropriate. Nevertheless, there
+ a multithreaded application to acquire a private copy of shared com-
+ piled code. However, it does not make a copy of the character tables
+ used by the compiled pattern; the new pattern code points to the same
+ tables as the original code. (See "Locale Support" below for details
+ of these character tables.) In many applications the same tables are
+ used throughout, so this behaviour is appropriate. Nevertheless, there
are occasions when a copy of a compiled pattern and the relevant tables
- are needed. The pcre2_code_copy_with_tables() provides this facility.
- Copies of both the code and the tables are made, with the new code
- pointing to the new tables. The memory for the new tables is automati-
- cally freed when pcre2_code_free() is called for the new copy of the
- compiled code.
+ are needed. The pcre2_code_copy_with_tables() provides this facility.
+ Copies of both the code and the tables are made, with the new code
+ pointing to the new tables. The memory for the new tables is automati-
+ cally freed when pcre2_code_free() is called for the new copy of the
+ compiled code. If pcre2_code_copy_withy_tables() is called with a NULL
+ argument, it returns NULL.
NOTE: When one of the matching functions is called, pointers to the
compiled pattern and the subject string are set in the match data block
@@ -2332,7 +2339,8 @@ THE MATCH DATA BLOCK
taken place.
When a match data block itself is no longer needed, it should be freed
- by calling pcre2_match_data_free().
+ by calling pcre2_match_data_free(). If this function is called with a
+ NULL argument, it returns immediately, without doing anything.
MATCHING A PATTERN: THE TRADITIONAL FUNCTION
@@ -2342,15 +2350,15 @@ MATCHING A PATTERN: THE TRADITIONAL FUNCTION
uint32_t options, pcre2_match_data *match_data,
pcre2_match_context *mcontext);
- The function pcre2_match() is called to match a subject string against
- a compiled pattern, which is passed in the code argument. You can call
+ The function pcre2_match() is called to match a subject string against
+ a compiled pattern, which is passed in the code argument. You can call
pcre2_match() with the same code argument as many times as you like, in
- order to find multiple matches in the subject string or to match dif-
+ order to find multiple matches in the subject string or to match dif-
ferent subject strings with the same pattern.
- This function is the main matching facility of the library, and it
- operates in a Perl-like manner. For specialist use there is also an
- alternative matching function, which is described below in the section
+ This function is the main matching facility of the library, and it
+ operates in a Perl-like manner. For specialist use there is also an
+ alternative matching function, which is described below in the section
about the pcre2_dfa_match() function.
Here is an example of a simple call to pcre2_match():
@@ -2365,187 +2373,187 @@ MATCHING A PATTERN: THE TRADITIONAL FUNCTION
md, /* the match data block */
NULL); /* a match context; NULL means use defaults */
- If the subject string is zero-terminated, the length can be given as
+ If the subject string is zero-terminated, the length can be given as
PCRE2_ZERO_TERMINATED. A match context must be provided if certain less
common matching parameters are to be changed. For details, see the sec-
tion on the match context above.
The string to be matched by pcre2_match()
- The subject string is passed to pcre2_match() as a pointer in subject,
- a length in length, and a starting offset in startoffset. The length
- and offset are in code units, not characters. That is, they are in
- bytes for the 8-bit library, 16-bit code units for the 16-bit library,
- and 32-bit code units for the 32-bit library, whether or not UTF pro-
+ The subject string is passed to pcre2_match() as a pointer in subject,
+ a length in length, and a starting offset in startoffset. The length
+ and offset are in code units, not characters. That is, they are in
+ bytes for the 8-bit library, 16-bit code units for the 16-bit library,
+ and 32-bit code units for the 32-bit library, whether or not UTF pro-
cessing is enabled.
If startoffset is greater than the length of the subject, pcre2_match()
- returns PCRE2_ERROR_BADOFFSET. When the starting offset is zero, the
- search for a match starts at the beginning of the subject, and this is
+ returns PCRE2_ERROR_BADOFFSET. When the starting offset is zero, the
+ search for a match starts at the beginning of the subject, and this is
by far the most common case. In UTF-8 or UTF-16 mode, the starting off-
- set must point to the start of a character, or to the end of the sub-
- ject (in UTF-32 mode, one code unit equals one character, so all off-
- sets are valid). Like the pattern string, the subject may contain
+ set must point to the start of a character, or to the end of the sub-
+ ject (in UTF-32 mode, one code unit equals one character, so all off-
+ sets are valid). Like the pattern string, the subject may contain
binary zeros.
- A non-zero starting offset is useful when searching for another match
- in the same subject by calling pcre2_match() again after a previous
- success. Setting startoffset differs from passing over a shortened
- string and setting PCRE2_NOTBOL in the case of a pattern that begins
+ A non-zero starting offset is useful when searching for another match
+ in the same subject by calling pcre2_match() again after a previous
+ success. Setting startoffset differs from passing over a shortened
+ string and setting PCRE2_NOTBOL in the case of a pattern that begins
with any kind of lookbehind. For example, consider the pattern
\Biss\B
- which finds occurrences of "iss" in the middle of words. (\B matches
- only if the current position in the subject is not a word boundary.)
+ which finds occurrences of "iss" in the middle of words. (\B matches
+ only if the current position in the subject is not a word boundary.)
When applied to the string "Mississipi" the first call to pcre2_match()
- finds the first occurrence. If pcre2_match() is called again with just
- the remainder of the subject, namely "issipi", it does not match,
+ finds the first occurrence. If pcre2_match() is called again with just
+ the remainder of the subject, namely "issipi", it does not match,
because \B is always false at the start of the subject, which is deemed
- to be a word boundary. However, if pcre2_match() is passed the entire
+ to be a word boundary. However, if pcre2_match() is passed the entire
string again, but with startoffset set to 4, it finds the second occur-
- rence of "iss" because it is able to look behind the starting point to
+ rence of "iss" because it is able to look behind the starting point to
discover that it is preceded by a letter.
- Finding all the matches in a subject is tricky when the pattern can
+ Finding all the matches in a subject is tricky when the pattern can
match an empty string. It is possible to emulate Perl's /g behaviour by
- first trying the match again at the same offset, with the
- PCRE2_NOTEMPTY_ATSTART and PCRE2_ANCHORED options, and then if that
- fails, advancing the starting offset and trying an ordinary match
- again. There is some code that demonstrates how to do this in the
- pcre2demo sample program. In the most general case, you have to check
- to see if the newline convention recognizes CRLF as a newline, and if
- so, and the current character is CR followed by LF, advance the start-
+ first trying the match again at the same offset, with the
+ PCRE2_NOTEMPTY_ATSTART and PCRE2_ANCHORED options, and then if that
+ fails, advancing the starting offset and trying an ordinary match
+ again. There is some code that demonstrates how to do this in the
+ pcre2demo sample program. In the most general case, you have to check
+ to see if the newline convention recognizes CRLF as a newline, and if
+ so, and the current character is CR followed by LF, advance the start-
ing offset by two characters instead of one.
If a non-zero starting offset is passed when the pattern is anchored, a
single attempt to match at the given offset is made. This can only suc-
- ceed if the pattern does not require the match to be at the start of
- the subject. In other words, the anchoring must be the result of set-
- ting the PCRE2_ANCHORED option or the use of .* with PCRE2_DOTALL, not
+ ceed if the pattern does not require the match to be at the start of
+ the subject. In other words, the anchoring must be the result of set-
+ ting the PCRE2_ANCHORED option or the use of .* with PCRE2_DOTALL, not
by starting the pattern with ^ or \A.
Option bits for pcre2_match()
The unused bits of the options argument for pcre2_match() must be zero.
- The only bits that may be set are PCRE2_ANCHORED, PCRE2_ENDANCHORED,
- PCRE2_NOTBOL, PCRE2_NOTEOL, PCRE2_NOTEMPTY, PCRE2_NOTEMPTY_ATSTART,
- PCRE2_NO_JIT, PCRE2_NO_UTF_CHECK, PCRE2_PARTIAL_HARD, and PCRE2_PAR-
+ The only bits that may be set are PCRE2_ANCHORED, PCRE2_ENDANCHORED,
+ PCRE2_NOTBOL, PCRE2_NOTEOL, PCRE2_NOTEMPTY, PCRE2_NOTEMPTY_ATSTART,
+ PCRE2_NO_JIT, PCRE2_NO_UTF_CHECK, PCRE2_PARTIAL_HARD, and PCRE2_PAR-
TIAL_SOFT. Their action is described below.
- Setting PCRE2_ANCHORED or PCRE2_ENDANCHORED at match time is not sup-
- ported by the just-in-time (JIT) compiler. If it is set, JIT matching
- is disabled and the interpretive code in pcre2_match() is run. Apart
- from PCRE2_NO_JIT (obviously), the remaining options are supported for
+ Setting PCRE2_ANCHORED or PCRE2_ENDANCHORED at match time is not sup-
+ ported by the just-in-time (JIT) compiler. If it is set, JIT matching
+ is disabled and the interpretive code in pcre2_match() is run. Apart
+ from PCRE2_NO_JIT (obviously), the remaining options are supported for
JIT matching.
PCRE2_ANCHORED
The PCRE2_ANCHORED option limits pcre2_match() to matching at the first
- matching position. If a pattern was compiled with PCRE2_ANCHORED, or
- turned out to be anchored by virtue of its contents, it cannot be made
- unachored at matching time. Note that setting the option at match time
+ matching position. If a pattern was compiled with PCRE2_ANCHORED, or
+ turned out to be anchored by virtue of its contents, it cannot be made
+ unachored at matching time. Note that setting the option at match time
disables JIT matching.
PCRE2_ENDANCHORED
- If the PCRE2_ENDANCHORED option is set, any string that pcre2_match()
- matches must be right at the end of the subject string. Note that set-
+ If the PCRE2_ENDANCHORED option is set, any string that pcre2_match()
+ matches must be right at the end of the subject string. Note that set-
ting the option at match time disables JIT matching.
PCRE2_NOTBOL
This option specifies that first character of the subject string is not
- the beginning of a line, so the circumflex metacharacter should not
- match before it. Setting this without having set PCRE2_MULTILINE at
+ the beginning of a line, so the circumflex metacharacter should not
+ match before it. Setting this without having set PCRE2_MULTILINE at
compile time causes circumflex never to match. This option affects only
the behaviour of the circumflex metacharacter. It does not affect \A.
PCRE2_NOTEOL
This option specifies that the end of the subject string is not the end
- of a line, so the dollar metacharacter should not match it nor (except
- in multiline mode) a newline immediately before it. Setting this with-
- out having set PCRE2_MULTILINE at compile time causes dollar never to
+ of a line, so the dollar metacharacter should not match it nor (except
+ in multiline mode) a newline immediately before it. Setting this with-
+ out having set PCRE2_MULTILINE at compile time causes dollar never to
match. This option affects only the behaviour of the dollar metacharac-
ter. It does not affect \Z or \z.
PCRE2_NOTEMPTY
An empty string is not considered to be a valid match if this option is
- set. If there are alternatives in the pattern, they are tried. If all
- the alternatives match the empty string, the entire match fails. For
+ set. If there are alternatives in the pattern, they are tried. If all
+ the alternatives match the empty string, the entire match fails. For
example, if the pattern
a?b?
- is applied to a string not beginning with "a" or "b", it matches an
+ is applied to a string not beginning with "a" or "b", it matches an
empty string at the start of the subject. With PCRE2_NOTEMPTY set, this
- match is not valid, so pcre2_match() searches further into the string
+ match is not valid, so pcre2_match() searches further into the string
for occurrences of "a" or "b".
PCRE2_NOTEMPTY_ATSTART
- This is like PCRE2_NOTEMPTY, except that it locks out an empty string
+ This is like PCRE2_NOTEMPTY, except that it locks out an empty string
match only at the first matching position, that is, at the start of the
- subject plus the starting offset. An empty string match later in the
- subject is permitted. If the pattern is anchored, such a match can
+ subject plus the starting offset. An empty string match later in the
+ subject is permitted. If the pattern is anchored, such a match can
occur only if the pattern contains \K.
PCRE2_NO_JIT
- By default, if a pattern has been successfully processed by
- pcre2_jit_compile(), JIT is automatically used when pcre2_match() is
- called with options that JIT supports. Setting PCRE2_NO_JIT disables
+ By default, if a pattern has been successfully processed by
+ pcre2_jit_compile(), JIT is automatically used when pcre2_match() is
+ called with options that JIT supports. Setting PCRE2_NO_JIT disables
the use of JIT; it forces matching to be done by the interpreter.
PCRE2_NO_UTF_CHECK
When PCRE2_UTF is set at compile time, the validity of the subject as a
- UTF string is checked by default when pcre2_match() is subsequently
- called. If a non-zero starting offset is given, the check is applied
- only to that part of the subject that could be inspected during match-
- ing, and there is a check that the starting offset points to the first
- code unit of a character or to the end of the subject. If there are no
- lookbehind assertions in the pattern, the check starts at the starting
- offset. Otherwise, it starts at the length of the longest lookbehind
+ UTF string is checked by default when pcre2_match() is subsequently
+ called. If a non-zero starting offset is given, the check is applied
+ only to that part of the subject that could be inspected during match-
+ ing, and there is a check that the starting offset points to the first
+ code unit of a character or to the end of the subject. If there are no
+ lookbehind assertions in the pattern, the check starts at the starting
+ offset. Otherwise, it starts at the length of the longest lookbehind
before the starting offset, or at the start of the subject if there are
- not that many characters before the starting offset. Note that the
+ not that many characters before the starting offset. Note that the
sequences \b and \B are one-character lookbehinds.
The check is carried out before any other processing takes place, and a
- negative error code is returned if the check fails. There are several
- UTF error codes for each code unit width, corresponding to different
- problems with the code unit sequence. There are discussions about the
- validity of UTF-8 strings, UTF-16 strings, and UTF-32 strings in the
+ negative error code is returned if the check fails. There are several
+ UTF error codes for each code unit width, corresponding to different
+ problems with the code unit sequence. There are discussions about the
+ validity of UTF-8 strings, UTF-16 strings, and UTF-32 strings in the
pcre2unicode page.
- If you know that your subject is valid, and you want to skip these
- checks for performance reasons, you can set the PCRE2_NO_UTF_CHECK
- option when calling pcre2_match(). You might want to do this for the
+ If you know that your subject is valid, and you want to skip these
+ checks for performance reasons, you can set the PCRE2_NO_UTF_CHECK
+ option when calling pcre2_match(). You might want to do this for the
second and subsequent calls to pcre2_match() if you are making repeated
calls to find other matches in the same subject string.
- Warning: When PCRE2_NO_UTF_CHECK is set, the effect of passing an
- invalid string as a subject, or an invalid value of startoffset, is
+ Warning: When PCRE2_NO_UTF_CHECK is set, the effect of passing an
+ invalid string as a subject, or an invalid value of startoffset, is
undefined. Your program may crash or loop indefinitely.
PCRE2_PARTIAL_HARD
PCRE2_PARTIAL_SOFT
- These options turn on the partial matching feature. A partial match
- occurs if the end of the subject string is reached successfully, but
- there are not enough subject characters to complete the match. If this
- happens when PCRE2_PARTIAL_SOFT (but not PCRE2_PARTIAL_HARD) is set,
- matching continues by testing any remaining alternatives. Only if no
- complete match can be found is PCRE2_ERROR_PARTIAL returned instead of
- PCRE2_ERROR_NOMATCH. In other words, PCRE2_PARTIAL_SOFT specifies that
- the caller is prepared to handle a partial match, but only if no com-
+ These options turn on the partial matching feature. A partial match
+ occurs if the end of the subject string is reached successfully, but
+ there are not enough subject characters to complete the match. If this
+ happens when PCRE2_PARTIAL_SOFT (but not PCRE2_PARTIAL_HARD) is set,
+ matching continues by testing any remaining alternatives. Only if no
+ complete match can be found is PCRE2_ERROR_PARTIAL returned instead of
+ PCRE2_ERROR_NOMATCH. In other words, PCRE2_PARTIAL_SOFT specifies that
+ the caller is prepared to handle a partial match, but only if no com-
plete match can be found.
- If PCRE2_PARTIAL_HARD is set, it overrides PCRE2_PARTIAL_SOFT. In this
- case, if a partial match is found, pcre2_match() immediately returns
- PCRE2_ERROR_PARTIAL, without considering any other alternatives. In
+ If PCRE2_PARTIAL_HARD is set, it overrides PCRE2_PARTIAL_SOFT. In this
+ case, if a partial match is found, pcre2_match() immediately returns
+ PCRE2_ERROR_PARTIAL, without considering any other alternatives. In
other words, when PCRE2_PARTIAL_HARD is set, a partial match is consid-
ered to be more important that an alternative complete match.
@@ -2555,38 +2563,38 @@ MATCHING A PATTERN: THE TRADITIONAL FUNCTION
NEWLINE HANDLING WHEN MATCHING
- When PCRE2 is built, a default newline convention is set; this is usu-
- ally the standard convention for the operating system. The default can
- be overridden in a compile context by calling pcre2_set_newline(). It
- can also be overridden by starting a pattern string with, for example,
- (*CRLF), as described in the section on newline conventions in the
- pcre2pattern page. During matching, the newline choice affects the be-
- haviour of the dot, circumflex, and dollar metacharacters. It may also
- alter the way the match starting position is advanced after a match
+ When PCRE2 is built, a default newline convention is set; this is usu-
+ ally the standard convention for the operating system. The default can
+ be overridden in a compile context by calling pcre2_set_newline(). It
+ can also be overridden by starting a pattern string with, for example,
+ (*CRLF), as described in the section on newline conventions in the
+ pcre2pattern page. During matching, the newline choice affects the be-
+ haviour of the dot, circumflex, and dollar metacharacters. It may also
+ alter the way the match starting position is advanced after a match
failure for an unanchored pattern.
When PCRE2_NEWLINE_CRLF, PCRE2_NEWLINE_ANYCRLF, or PCRE2_NEWLINE_ANY is
- set as the newline convention, and a match attempt for an unanchored
+ set as the newline convention, and a match attempt for an unanchored
pattern fails when the current starting position is at a CRLF sequence,
- and the pattern contains no explicit matches for CR or LF characters,
- the match position is advanced by two characters instead of one, in
+ and the pattern contains no explicit matches for CR or LF characters,
+ the match position is advanced by two characters instead of one, in
other words, to after the CRLF.
The above rule is a compromise that makes the most common cases work as
- expected. For example, if the pattern is .+A (and the PCRE2_DOTALL
+ expected. For example, if the pattern is .+A (and the PCRE2_DOTALL
option is not set), it does not match the string "\r\nA" because, after
- failing at the start, it skips both the CR and the LF before retrying.
- However, the pattern [\r\n]A does match that string, because it con-
+ failing at the start, it skips both the CR and the LF before retrying.
+ However, the pattern [\r\n]A does match that string, because it con-
tains an explicit CR or LF reference, and so advances only by one char-
acter after the first failure.
An explicit match for CR of LF is either a literal appearance of one of
- those characters in the pattern, or one of the \r or \n or equivalent
+ those characters in the pattern, or one of the \r or \n or equivalent
octal or hexadecimal escape sequences. Implicit matches such as [^X] do
- not count, nor does \s, even though it includes CR and LF in the char-
+ not count, nor does \s, even though it includes CR and LF in the char-
acters that it matches.
- Notwithstanding the above, anomalous effects may still occur when CRLF
+ Notwithstanding the above, anomalous effects may still occur when CRLF
is a valid newline sequence and explicit \r or \n escapes appear in the
pattern.
@@ -2597,81 +2605,81 @@ HOW PCRE2_MATCH() RETURNS A STRING AND CAPTURED SUBSTRINGS
PCRE2_SIZE *pcre2_get_ovector_pointer(pcre2_match_data *match_data);
- In general, a pattern matches a certain portion of the subject, and in
- addition, further substrings from the subject may be picked out by
- parenthesized parts of the pattern. Following the usage in Jeffrey
- Friedl's book, this is called "capturing" in what follows, and the
- phrase "capturing subpattern" or "capturing group" is used for a frag-
- ment of a pattern that picks out a substring. PCRE2 supports several
+ In general, a pattern matches a certain portion of the subject, and in
+ addition, further substrings from the subject may be picked out by
+ parenthesized parts of the pattern. Following the usage in Jeffrey
+ Friedl's book, this is called "capturing" in what follows, and the
+ phrase "capturing subpattern" or "capturing group" is used for a frag-
+ ment of a pattern that picks out a substring. PCRE2 supports several
other kinds of parenthesized subpattern that do not cause substrings to
- be captured. The pcre2_pattern_info() function can be used to find out
+ be captured. The pcre2_pattern_info() function can be used to find out
how many capturing subpatterns there are in a compiled pattern.
- You can use auxiliary functions for accessing captured substrings by
+ You can use auxiliary functions for accessing captured substrings by
number or by name, as described in sections below.
Alternatively, you can make direct use of the vector of PCRE2_SIZE val-
- ues, called the ovector, which contains the offsets of captured
- strings. It is part of the match data block. The function
- pcre2_get_ovector_pointer() returns the address of the ovector, and
+ ues, called the ovector, which contains the offsets of captured
+ strings. It is part of the match data block. The function
+ pcre2_get_ovector_pointer() returns the address of the ovector, and
pcre2_get_ovector_count() returns the number of pairs of values it con-
tains.
Within the ovector, the first in each pair of values is set to the off-
set of the first code unit of a substring, and the second is set to the
- offset of the first code unit after the end of a substring. These val-
- ues are always code unit offsets, not character offsets. That is, they
- are byte offsets in the 8-bit library, 16-bit offsets in the 16-bit
+ offset of the first code unit after the end of a substring. These val-
+ ues are always code unit offsets, not character offsets. That is, they
+ are byte offsets in the 8-bit library, 16-bit offsets in the 16-bit
library, and 32-bit offsets in the 32-bit library.
- After a partial match (error return PCRE2_ERROR_PARTIAL), only the
- first pair of offsets (that is, ovector[0] and ovector[1]) are set.
- They identify the part of the subject that was partially matched. See
+ After a partial match (error return PCRE2_ERROR_PARTIAL), only the
+ first pair of offsets (that is, ovector[0] and ovector[1]) are set.
+ They identify the part of the subject that was partially matched. See
the pcre2partial documentation for details of partial matching.
- After a fully successful match, the first pair of offsets identifies
- the portion of the subject string that was matched by the entire pat-
- tern. The next pair is used for the first captured substring, and so
- on. The value returned by pcre2_match() is one more than the highest
- numbered pair that has been set. For example, if two substrings have
- been captured, the returned value is 3. If there are no captured sub-
+ After a fully successful match, the first pair of offsets identifies
+ the portion of the subject string that was matched by the entire pat-
+ tern. The next pair is used for the first captured substring, and so
+ on. The value returned by pcre2_match() is one more than the highest
+ numbered pair that has been set. For example, if two substrings have
+ been captured, the returned value is 3. If there are no captured sub-
strings, the return value from a successful match is 1, indicating that
just the first pair of offsets has been set.
- If a pattern uses the \K escape sequence within a positive assertion,
+ If a pattern uses the \K escape sequence within a positive assertion,
the reported start of a successful match can be greater than the end of
- the match. For example, if the pattern (?=ab\K) is matched against
+ the match. For example, if the pattern (?=ab\K) is matched against
"ab", the start and end offset values for the match are 2 and 0.
- If a capturing subpattern group is matched repeatedly within a single
- match operation, it is the last portion of the subject that it matched
+ If a capturing subpattern group is matched repeatedly within a single
+ match operation, it is the last portion of the subject that it matched
that is returned.
If the ovector is too small to hold all the captured substring offsets,
- as much as possible is filled in, and the function returns a value of
- zero. If captured substrings are not of interest, pcre2_match() may be
+ as much as possible is filled in, and the function returns a value of
+ zero. If captured substrings are not of interest, pcre2_match() may be
called with a match data block whose ovector is of minimum length (that
is, one pair).
- It is possible for capturing subpattern number n+1 to match some part
+ It is possible for capturing subpattern number n+1 to match some part
of the subject when subpattern n has not been used at all. For example,
- if the string "abc" is matched against the pattern (a|(z))(bc) the
+ if the string "abc" is matched against the pattern (a|(z))(bc) the
return from the function is 4, and subpatterns 1 and 3 are matched, but
- 2 is not. When this happens, both values in the offset pairs corre-
+ 2 is not. When this happens, both values in the offset pairs corre-
sponding to unused subpatterns are set to PCRE2_UNSET.
- Offset values that correspond to unused subpatterns at the end of the
- expression are also set to PCRE2_UNSET. For example, if the string
+ Offset values that correspond to unused subpatterns at the end of the
+ expression are also set to PCRE2_UNSET. For example, if the string
"abc" is matched against the pattern (abc)(x(yz)?)? subpatterns 2 and 3
- are not matched. The return from the function is 2, because the high-
+ are not matched. The return from the function is 2, because the high-
est used capturing subpattern number is 1. The offsets for for the sec-
- ond and third capturing subpatterns (assuming the vector is large
+ ond and third capturing subpatterns (assuming the vector is large
enough, of course) are set to PCRE2_UNSET.
Elements in the ovector that do not correspond to capturing parentheses
in the pattern are never changed. That is, if a pattern contains n cap-
turing parentheses, no more than ovector[0] to ovector[2n+1] are set by
- pcre2_match(). The other elements retain whatever values they previ-
+ pcre2_match(). The other elements retain whatever values they previ-
ously had.
@@ -2681,69 +2689,69 @@ OTHER INFORMATION ABOUT A MATCH
PCRE2_SIZE pcre2_get_startchar(pcre2_match_data *match_data);
- As well as the offsets in the ovector, other information about a match
- is retained in the match data block and can be retrieved by the above
- functions in appropriate circumstances. If they are called at other
+ As well as the offsets in the ovector, other information about a match
+ is retained in the match data block and can be retrieved by the above
+ functions in appropriate circumstances. If they are called at other
times, the result is undefined.
- After a successful match, a partial match (PCRE2_ERROR_PARTIAL), or a
+ After a successful match, a partial match (PCRE2_ERROR_PARTIAL), or a
failure to match (PCRE2_ERROR_NOMATCH), a (*MARK), (*PRUNE), or (*THEN)
- name may be available. The function pcre2_get_mark() can be called to
- access this name. The same function applies to all three verbs. It
+ name may be available. The function pcre2_get_mark() can be called to
+ access this name. The same function applies to all three verbs. It
returns a pointer to the zero-terminated name, which is within the com-
piled pattern. If no name is available, NULL is returned. The length of
- the name (excluding the terminating zero) is stored in the code unit
- that precedes the name. You should use this length instead of relying
+ the name (excluding the terminating zero) is stored in the code unit
+ that precedes the name. You should use this length instead of relying
on the terminating zero if the name might contain a binary zero.
- After a successful match, the name that is returned is the last
- (*MARK), (*PRUNE), or (*THEN) name encountered on the matching path
- through the pattern. Instances of (*PRUNE) and (*THEN) without names
- are ignored. Thus, for example, if the matching path contains
- (*MARK:A)(*PRUNE), the name "A" is returned. After a "no match" or a
- partial match, the last encountered name is returned. For example,
+ After a successful match, the name that is returned is the last
+ (*MARK), (*PRUNE), or (*THEN) name encountered on the matching path
+ through the pattern. Instances of (*PRUNE) and (*THEN) without names
+ are ignored. Thus, for example, if the matching path contains
+ (*MARK:A)(*PRUNE), the name "A" is returned. After a "no match" or a
+ partial match, the last encountered name is returned. For example,
consider this pattern:
^(*MARK:A)((*MARK:B)a|b)c
- When it matches "bc", the returned name is A. The B mark is "seen" in
- the first branch of the group, but it is not on the matching path. On
- the other hand, when this pattern fails to match "bx", the returned
+ When it matches "bc", the returned name is A. The B mark is "seen" in
+ the first branch of the group, but it is not on the matching path. On
+ the other hand, when this pattern fails to match "bx", the returned
name is B.
- Warning: By default, certain start-of-match optimizations are used to
- give a fast "no match" result in some situations. For example, if the
- anchoring is removed from the pattern above, there is an initial check
- for the presence of "c" in the subject before running the matching
+ Warning: By default, certain start-of-match optimizations are used to
+ give a fast "no match" result in some situations. For example, if the
+ anchoring is removed from the pattern above, there is an initial check
+ for the presence of "c" in the subject before running the matching
engine. This check fails for "bx", causing a match failure without see-
ing any marks. You can disable the start-of-match optimizations by set-
ting the PCRE2_NO_START_OPTIMIZE option for pcre2_compile() or starting
the pattern with (*NO_START_OPT).
- After a successful match, a partial match, or one of the invalid UTF
- errors (for example, PCRE2_ERROR_UTF8_ERR5), pcre2_get_startchar() can
+ After a successful match, a partial match, or one of the invalid UTF
+ errors (for example, PCRE2_ERROR_UTF8_ERR5), pcre2_get_startchar() can
be called. After a successful or partial match it returns the code unit
- offset of the character at which the match started. For a non-partial
- match, this can be different to the value of ovector[0] if the pattern
- contains the \K escape sequence. After a partial match, however, this
- value is always the same as ovector[0] because \K does not affect the
+ offset of the character at which the match started. For a non-partial
+ match, this can be different to the value of ovector[0] if the pattern
+ contains the \K escape sequence. After a partial match, however, this
+ value is always the same as ovector[0] because \K does not affect the
result of a partial match.
- After a UTF check failure, pcre2_get_startchar() can be used to obtain
+ After a UTF check failure, pcre2_get_startchar() can be used to obtain
the code unit offset of the invalid UTF character. Details are given in
the pcre2unicode page.
ERROR RETURNS FROM pcre2_match()
- If pcre2_match() fails, it returns a negative number. This can be con-
- verted to a text string by calling the pcre2_get_error_message() func-
- tion (see "Obtaining a textual error message" below). Negative error
- codes are also returned by other functions, and are documented with
- them. The codes are given names in the header file. If UTF checking is
+ If pcre2_match() fails, it returns a negative number. This can be con-
+ verted to a text string by calling the pcre2_get_error_message() func-
+ tion (see "Obtaining a textual error message" below). Negative error
+ codes are also returned by other functions, and are documented with
+ them. The codes are given names in the header file. If UTF checking is
in force and an invalid UTF subject string is detected, one of a number
- of UTF-specific negative error codes is returned. Details are given in
- the pcre2unicode page. The following are the other errors that may be
+ of UTF-specific negative error codes is returned. Details are given in
+ the pcre2unicode page. The following are the other errors that may be
returned by pcre2_match():
PCRE2_ERROR_NOMATCH
@@ -2752,20 +2760,20 @@ ERROR RETURNS FROM pcre2_match()
PCRE2_ERROR_PARTIAL
- The subject string did not match, but it did match partially. See the
+ The subject string did not match, but it did match partially. See the
pcre2partial documentation for details of partial matching.
PCRE2_ERROR_BADMAGIC
PCRE2 stores a 4-byte "magic number" at the start of the compiled code,
- to catch the case when it is passed a junk pointer. This is the error
+ to catch the case when it is passed a junk pointer. This is the error
that is returned when the magic number is not present.
PCRE2_ERROR_BADMODE
- This error is given when a compiled pattern is passed to a function in
- a library of a different code unit width, for example, a pattern com-
- piled by the 8-bit library is passed to a 16-bit or 32-bit library
+ This error is given when a compiled pattern is passed to a function in
+ a library of a different code unit width, for example, a pattern com-
+ piled by the 8-bit library is passed to a 16-bit or 32-bit library
function.
PCRE2_ERROR_BADOFFSET
@@ -2779,15 +2787,15 @@ ERROR RETURNS FROM pcre2_match()
PCRE2_ERROR_BADUTFOFFSET
The UTF code unit sequence that was passed as a subject was checked and
- found to be valid (the PCRE2_NO_UTF_CHECK option was not set), but the
- value of startoffset did not point to the beginning of a UTF character
+ found to be valid (the PCRE2_NO_UTF_CHECK option was not set), but the
+ value of startoffset did not point to the beginning of a UTF character
or the end of the subject.
PCRE2_ERROR_CALLOUT
- This error is never generated by pcre2_match() itself. It is provided
- for use by callout functions that want to cause pcre2_match() or
- pcre2_callout_enumerate() to return a distinctive error code. See the
+ This error is never generated by pcre2_match() itself. It is provided
+ for use by callout functions that want to cause pcre2_match() or
+ pcre2_callout_enumerate() to return a distinctive error code. See the
pcre2callout documentation for details.
PCRE2_ERROR_DEPTHLIMIT
@@ -2800,14 +2808,14 @@ ERROR RETURNS FROM pcre2_match()
PCRE2_ERROR_INTERNAL
- An unexpected internal error has occurred. This error could be caused
+ An unexpected internal error has occurred. This error could be caused
by a bug in PCRE2 or by overwriting of the compiled pattern.
PCRE2_ERROR_JIT_STACKLIMIT
- This error is returned when a pattern that was successfully studied
- using JIT is being matched, but the memory available for the just-in-
- time processing stack is not large enough. See the pcre2jit documenta-
+ This error is returned when a pattern that was successfully studied
+ using JIT is being matched, but the memory available for the just-in-
+ time processing stack is not large enough. See the pcre2jit documenta-
tion for more details.
PCRE2_ERROR_MATCHLIMIT
@@ -2816,10 +2824,10 @@ ERROR RETURNS FROM pcre2_match()
PCRE2_ERROR_NOMEMORY
- If a pattern contains many nested backtracking points, heap memory is
- used to remember them. This error is given when the memory allocation
- function (default or custom) fails. Note that a different error,
- PCRE2_ERROR_HEAPLIMIT, is given if the amount of memory needed exceeds
+ If a pattern contains many nested backtracking points, heap memory is
+ used to remember them. This error is given when the memory allocation
+ function (default or custom) fails. Note that a different error,
+ PCRE2_ERROR_HEAPLIMIT, is given if the amount of memory needed exceeds
the heap limit.
PCRE2_ERROR_NULL
@@ -2828,12 +2836,12 @@ ERROR RETURNS FROM pcre2_match()
PCRE2_ERROR_RECURSELOOP
- This error is returned when pcre2_match() detects a recursion loop
- within the pattern. Specifically, it means that either the whole pat-
+ This error is returned when pcre2_match() detects a recursion loop
+ within the pattern. Specifically, it means that either the whole pat-
tern or a subpattern has been called recursively for the second time at
- the same position in the subject string. Some simple patterns that
- might do this are detected and faulted at compile time, but more com-
- plicated cases, in particular mutual recursions between two different
+ the same position in the subject string. Some simple patterns that
+ might do this are detected and faulted at compile time, but more com-
+ plicated cases, in particular mutual recursions between two different
subpatterns, cannot be detected until matching is attempted.
@@ -2842,20 +2850,20 @@ OBTAINING A TEXTUAL ERROR MESSAGE
int pcre2_get_error_message(int errorcode, PCRE2_UCHAR *buffer,
PCRE2_SIZE bufflen);
- A text message for an error code from any PCRE2 function (compile,
- match, or auxiliary) can be obtained by calling pcre2_get_error_mes-
- sage(). The code is passed as the first argument, with the remaining
- two arguments specifying a code unit buffer and its length in code
- units, into which the text message is placed. The message is returned
- in code units of the appropriate width for the library that is being
+ A text message for an error code from any PCRE2 function (compile,
+ match, or auxiliary) can be obtained by calling pcre2_get_error_mes-
+ sage(). The code is passed as the first argument, with the remaining
+ two arguments specifying a code unit buffer and its length in code
+ units, into which the text message is placed. The message is returned
+ in code units of the appropriate width for the library that is being
used.
- The returned message is terminated with a trailing zero, and the func-
- tion returns the number of code units used, excluding the trailing
+ The returned message is terminated with a trailing zero, and the func-
+ tion returns the number of code units used, excluding the trailing
zero. If the error number is unknown, the negative error code
- PCRE2_ERROR_BADDATA is returned. If the buffer is too small, the mes-
- sage is truncated (but still with a trailing zero), and the negative
- error code PCRE2_ERROR_NOMEMORY is returned. None of the messages are
+ PCRE2_ERROR_BADDATA is returned. If the buffer is too small, the mes-
+ sage is truncated (but still with a trailing zero), and the negative
+ error code PCRE2_ERROR_NOMEMORY is returned. None of the messages are
very long; a buffer size of 120 code units is ample.
@@ -2874,39 +2882,39 @@ EXTRACTING CAPTURED SUBSTRINGS BY NUMBER
void pcre2_substring_free(PCRE2_UCHAR *buffer);
- Captured substrings can be accessed directly by using the ovector as
+ Captured substrings can be accessed directly by using the ovector as
described above. For convenience, auxiliary functions are provided for
- extracting captured substrings as new, separate, zero-terminated
+ extracting captured substrings as new, separate, zero-terminated
strings. A substring that contains a binary zero is correctly extracted
- and has a further zero added on the end, but the result is not, of
+ and has a further zero added on the end, but the result is not, of
course, a C string.
The functions in this section identify substrings by number. The number
zero refers to the entire matched substring, with higher numbers refer-
- ring to substrings captured by parenthesized groups. After a partial
- match, only substring zero is available. An attempt to extract any
- other substring gives the error PCRE2_ERROR_PARTIAL. The next section
+ ring to substrings captured by parenthesized groups. After a partial
+ match, only substring zero is available. An attempt to extract any
+ other substring gives the error PCRE2_ERROR_PARTIAL. The next section
describes similar functions for extracting captured substrings by name.
- If a pattern uses the \K escape sequence within a positive assertion,
+ If a pattern uses the \K escape sequence within a positive assertion,
the reported start of a successful match can be greater than the end of
- the match. For example, if the pattern (?=ab\K) is matched against
- "ab", the start and end offset values for the match are 2 and 0. In
- this situation, calling these functions with a zero substring number
+ the match. For example, if the pattern (?=ab\K) is matched against
+ "ab", the start and end offset values for the match are 2 and 0. In
+ this situation, calling these functions with a zero substring number
extracts a zero-length empty string.
- You can find the length in code units of a captured substring without
- extracting it by calling pcre2_substring_length_bynumber(). The first
- argument is a pointer to the match data block, the second is the group
- number, and the third is a pointer to a variable into which the length
- is placed. If you just want to know whether or not the substring has
+ You can find the length in code units of a captured substring without
+ extracting it by calling pcre2_substring_length_bynumber(). The first
+ argument is a pointer to the match data block, the second is the group
+ number, and the third is a pointer to a variable into which the length
+ is placed. If you just want to know whether or not the substring has
been captured, you can pass the third argument as NULL.
- The pcre2_substring_copy_bynumber() function copies a captured sub-
- string into a supplied buffer, whereas pcre2_substring_get_bynumber()
- copies it into new memory, obtained using the same memory allocation
- function that was used for the match data block. The first two argu-
- ments of these functions are a pointer to the match data block and a
+ The pcre2_substring_copy_bynumber() function copies a captured sub-
+ string into a supplied buffer, whereas pcre2_substring_get_bynumber()
+ copies it into new memory, obtained using the same memory allocation
+ function that was used for the match data block. The first two argu-
+ ments of these functions are a pointer to the match data block and a
capturing group number.
The final arguments of pcre2_substring_copy_bynumber() are a pointer to
@@ -2915,25 +2923,25 @@ EXTRACTING CAPTURED SUBSTRINGS BY NUMBER
for the extracted substring, excluding the terminating zero.
For pcre2_substring_get_bynumber() the third and fourth arguments point
- to variables that are updated with a pointer to the new memory and the
- number of code units that comprise the substring, again excluding the
- terminating zero. When the substring is no longer needed, the memory
+ to variables that are updated with a pointer to the new memory and the
+ number of code units that comprise the substring, again excluding the
+ terminating zero. When the substring is no longer needed, the memory
should be freed by calling pcre2_substring_free().
- The return value from all these functions is zero for success, or a
- negative error code. If the pattern match failed, the match failure
- code is returned. If a substring number greater than zero is used
- after a partial match, PCRE2_ERROR_PARTIAL is returned. Other possible
+ The return value from all these functions is zero for success, or a
+ negative error code. If the pattern match failed, the match failure
+ code is returned. If a substring number greater than zero is used
+ after a partial match, PCRE2_ERROR_PARTIAL is returned. Other possible
error codes are:
PCRE2_ERROR_NOMEMORY
- The buffer was too small for pcre2_substring_copy_bynumber(), or the
+ The buffer was too small for pcre2_substring_copy_bynumber(), or the
attempt to get memory failed for pcre2_substring_get_bynumber().
PCRE2_ERROR_NOSUBSTRING
- There is no substring with that number in the pattern, that is, the
+ There is no substring with that number in the pattern, that is, the
number is greater than the number of capturing parentheses.
PCRE2_ERROR_UNAVAILABLE
@@ -2944,8 +2952,8 @@ EXTRACTING CAPTURED SUBSTRINGS BY NUMBER
PCRE2_ERROR_UNSET
- The substring did not participate in the match. For example, if the
- pattern is (abc)|(def) and the subject is "def", and the ovector con-
+ The substring did not participate in the match. For example, if the
+ pattern is (abc)|(def) and the subject is "def", and the ovector con-
tains at least two capturing slots, substring number 1 is unset.
@@ -2956,32 +2964,32 @@ EXTRACTING A LIST OF ALL CAPTURED SUBSTRINGS
void pcre2_substring_list_free(PCRE2_SPTR *list);
- The pcre2_substring_list_get() function extracts all available sub-
- strings and builds a list of pointers to them. It also (optionally)
- builds a second list that contains their lengths (in code units),
+ The pcre2_substring_list_get() function extracts all available sub-
+ strings and builds a list of pointers to them. It also (optionally)
+ builds a second list that contains their lengths (in code units),
excluding a terminating zero that is added to each of them. All this is
done in a single block of memory that is obtained using the same memory
allocation function that was used to get the match data block.
- This function must be called only after a successful match. If called
+ This function must be called only after a successful match. If called
after a partial match, the error code PCRE2_ERROR_PARTIAL is returned.
- The address of the memory block is returned via listptr, which is also
+ The address of the memory block is returned via listptr, which is also
the start of the list of string pointers. The end of the list is marked
- by a NULL pointer. The address of the list of lengths is returned via
- lengthsptr. If your strings do not contain binary zeros and you do not
+ by a NULL pointer. The address of the list of lengths is returned via
+ lengthsptr. If your strings do not contain binary zeros and you do not
therefore need the lengths, you may supply NULL as the lengthsptr argu-
- ment to disable the creation of a list of lengths. The yield of the
- function is zero if all went well, or PCRE2_ERROR_NOMEMORY if the mem-
- ory block could not be obtained. When the list is no longer needed, it
+ ment to disable the creation of a list of lengths. The yield of the
+ function is zero if all went well, or PCRE2_ERROR_NOMEMORY if the mem-
+ ory block could not be obtained. When the list is no longer needed, it
should be freed by calling pcre2_substring_list_free().
If this function encounters a substring that is unset, which can happen
- when capturing subpattern number n+1 matches some part of the subject,
- but subpattern n has not been used at all, it returns an empty string.
- This can be distinguished from a genuine zero-length substring by
+ when capturing subpattern number n+1 matches some part of the subject,
+ but subpattern n has not been used at all, it returns an empty string.
+ This can be distinguished from a genuine zero-length substring by
inspecting the appropriate offset in the ovector, which contain
- PCRE2_UNSET for unset substrings, or by calling pcre2_sub-
+ PCRE2_UNSET for unset substrings, or by calling pcre2_sub-
string_length_bynumber().
@@ -3001,39 +3009,39 @@ EXTRACTING CAPTURED SUBSTRINGS BY NAME
void pcre2_substring_free(PCRE2_UCHAR *buffer);
- To extract a substring by name, you first have to find associated num-
+ To extract a substring by name, you first have to find associated num-
ber. For example, for this pattern:
(a+)b(?\d+)...
the number of the subpattern called "xxx" is 2. If the name is known to
- be unique (PCRE2_DUPNAMES was not set), you can find the number from
+ be unique (PCRE2_DUPNAMES was not set), you can find the number from
the name by calling pcre2_substring_number_from_name(). The first argu-
- ment is the compiled pattern, and the second is the name. The yield of
+ ment is the compiled pattern, and the second is the name. The yield of
the function is the subpattern number, PCRE2_ERROR_NOSUBSTRING if there
- is no subpattern of that name, or PCRE2_ERROR_NOUNIQUESUBSTRING if
- there is more than one subpattern of that name. Given the number, you
- can extract the substring directly from the ovector, or use one of the
+ is no subpattern of that name, or PCRE2_ERROR_NOUNIQUESUBSTRING if
+ there is more than one subpattern of that name. Given the number, you
+ can extract the substring directly from the ovector, or use one of the
"bynumber" functions described above.
- For convenience, there are also "byname" functions that correspond to
- the "bynumber" functions, the only difference being that the second
- argument is a name instead of a number. If PCRE2_DUPNAMES is set and
+ For convenience, there are also "byname" functions that correspond to
+ the "bynumber" functions, the only difference being that the second
+ argument is a name instead of a number. If PCRE2_DUPNAMES is set and
there are duplicate names, these functions scan all the groups with the
given name, and return the first named string that is set.
- If there are no groups with the given name, PCRE2_ERROR_NOSUBSTRING is
- returned. If all groups with the name have numbers that are greater
- than the number of slots in the ovector, PCRE2_ERROR_UNAVAILABLE is
- returned. If there is at least one group with a slot in the ovector,
+ If there are no groups with the given name, PCRE2_ERROR_NOSUBSTRING is
+ returned. If all groups with the name have numbers that are greater
+ than the number of slots in the ovector, PCRE2_ERROR_UNAVAILABLE is
+ returned. If there is at least one group with a slot in the ovector,
but no group is found to be set, PCRE2_ERROR_UNSET is returned.
Warning: If the pattern uses the (?| feature to set up multiple subpat-
- terns with the same number, as described in the section on duplicate
- subpattern numbers in the pcre2pattern page, you cannot use names to
- distinguish the different subpatterns, because names are not included
- in the compiled code. The matching process uses only numbers. For this
- reason, the use of different names for subpatterns of the same number
+ terns with the same number, as described in the section on duplicate
+ subpattern numbers in the pcre2pattern page, you cannot use names to
+ distinguish the different subpatterns, because names are not included
+ in the compiled code. The matching process uses only numbers. For this
+ reason, the use of different names for subpatterns of the same number
causes an error at compile time.
@@ -3046,80 +3054,80 @@ CREATING A NEW STRING WITH SUBSTITUTIONS
PCRE2_SIZE rlength, PCRE2_UCHAR *outputbufferP,
PCRE2_SIZE *outlengthptr);
- This function calls pcre2_match() and then makes a copy of the subject
- string in outputbuffer, replacing the part that was matched with the
- replacement string, whose length is supplied in rlength. This can be
+ This function calls pcre2_match() and then makes a copy of the subject
+ string in outputbuffer, replacing the part that was matched with the
+ replacement string, whose length is supplied in rlength. This can be
given as PCRE2_ZERO_TERMINATED for a zero-terminated string. Matches in
- which a \K item in a lookahead in the pattern causes the match to end
+ which a \K item in a lookahead in the pattern causes the match to end
before it starts are not supported, and give rise to an error return.
- The first seven arguments of pcre2_substitute() are the same as for
+ The first seven arguments of pcre2_substitute() are the same as for
pcre2_match(), except that the partial matching options are not permit-
- ted, and match_data may be passed as NULL, in which case a match data
- block is obtained and freed within this function, using memory manage-
- ment functions from the match context, if provided, or else those that
+ ted, and match_data may be passed as NULL, in which case a match data
+ block is obtained and freed within this function, using memory manage-
+ ment functions from the match context, if provided, or else those that
were used to allocate memory for the compiled code.
- The outlengthptr argument must point to a variable that contains the
- length, in code units, of the output buffer. If the function is suc-
- cessful, the value is updated to contain the length of the new string,
+ The outlengthptr argument must point to a variable that contains the
+ length, in code units, of the output buffer. If the function is suc-
+ cessful, the value is updated to contain the length of the new string,
excluding the trailing zero that is automatically added.
- If the function is not successful, the value set via outlengthptr
- depends on the type of error. For syntax errors in the replacement
- string, the value is the offset in the replacement string where the
- error was detected. For other errors, the value is PCRE2_UNSET by
- default. This includes the case of the output buffer being too small,
- unless PCRE2_SUBSTITUTE_OVERFLOW_LENGTH is set (see below), in which
- case the value is the minimum length needed, including space for the
- trailing zero. Note that in order to compute the required length,
- pcre2_substitute() has to simulate all the matching and copying,
+ If the function is not successful, the value set via outlengthptr
+ depends on the type of error. For syntax errors in the replacement
+ string, the value is the offset in the replacement string where the
+ error was detected. For other errors, the value is PCRE2_UNSET by
+ default. This includes the case of the output buffer being too small,
+ unless PCRE2_SUBSTITUTE_OVERFLOW_LENGTH is set (see below), in which
+ case the value is the minimum length needed, including space for the
+ trailing zero. Note that in order to compute the required length,
+ pcre2_substitute() has to simulate all the matching and copying,
instead of giving an error return as soon as the buffer overflows. Note
also that the length is in code units, not bytes.
- In the replacement string, which is interpreted as a UTF string in UTF
- mode, and is checked for UTF validity unless the PCRE2_NO_UTF_CHECK
+ In the replacement string, which is interpreted as a UTF string in UTF
+ mode, and is checked for UTF validity unless the PCRE2_NO_UTF_CHECK
option is set, a dollar character is an escape character that can spec-
- ify the insertion of characters from capturing groups or (*MARK),
- (*PRUNE), or (*THEN) items in the pattern. The following forms are
+ ify the insertion of characters from capturing groups or (*MARK),
+ (*PRUNE), or (*THEN) items in the pattern. The following forms are
always recognized:
$$ insert a dollar character
$ or ${} insert the contents of group
$*MARK or ${*MARK} insert a (*MARK), (*PRUNE), or (*THEN) name
- Either a group number or a group name can be given for . Curly
- brackets are required only if the following character would be inter-
+ Either a group number or a group name can be given for . Curly
+ brackets are required only if the following character would be inter-
preted as part of the number or name. The number may be zero to include
- the entire matched string. For example, if the pattern a(b)c is
- matched with "=abc=" and the replacement string "+$1$0$1+", the result
+ the entire matched string. For example, if the pattern a(b)c is
+ matched with "=abc=" and the replacement string "+$1$0$1+", the result
is "=+babcb+=".
$*MARK inserts the name from the last encountered (*MARK), (*PRUNE), or
- (*THEN) on the matching path that has a name. (*MARK) must always
- include a name, but (*PRUNE) and (*THEN) need not. For example, in the
- case of (*MARK:A)(*PRUNE) the name inserted is "A", but for
- (*MARK:A)(*PRUNE:B) the relevant name is "B". This facility can be
- used to perform simple simultaneous substitutions, as this pcre2test
+ (*THEN) on the matching path that has a name. (*MARK) must always
+ include a name, but (*PRUNE) and (*THEN) need not. For example, in the
+ case of (*MARK:A)(*PRUNE) the name inserted is "A", but for
+ (*MARK:A)(*PRUNE:B) the relevant name is "B". This facility can be
+ used to perform simple simultaneous substitutions, as this pcre2test
example shows:
/(*MARK:pear)apple|(*MARK:orange)lemon/g,replace=${*MARK}
apple lemon
2: pear orange
- As well as the usual options for pcre2_match(), a number of additional
+ As well as the usual options for pcre2_match(), a number of additional
options can be set in the options argument of pcre2_substitute().
PCRE2_SUBSTITUTE_GLOBAL causes the function to iterate over the subject
- string, replacing every matching substring. If this option is not set,
- only the first matching substring is replaced. The search for matches
- takes place in the original subject string (that is, previous replace-
- ments do not affect it). Iteration is implemented by advancing the
- startoffset value for each search, which is always passed the entire
+ string, replacing every matching substring. If this option is not set,
+ only the first matching substring is replaced. The search for matches
+ takes place in the original subject string (that is, previous replace-
+ ments do not affect it). Iteration is implemented by advancing the
+ startoffset value for each search, which is always passed the entire
subject string. If an offset limit is set in the match context, search-
ing stops when that limit is reached.
- You can restrict the effect of a global substitution to a portion of
+ You can restrict the effect of a global substitution to a portion of
the subject string by setting either or both of startoffset and an off-
set limit. Here is a pcre2test example:
@@ -3127,87 +3135,87 @@ CREATING A NEW STRING WITH SUBSTITUTIONS
ABC ABC ABC ABC\=offset=3,offset_limit=12
2: ABC A!C A!C ABC
- When continuing with global substitutions after matching a substring
+ When continuing with global substitutions after matching a substring
with zero length, an attempt to find a non-empty match at the same off-
set is performed. If this is not successful, the offset is advanced by
one character except when CRLF is a valid newline sequence and the next
- two characters are CR, LF. In this case, the offset is advanced by two
+ two characters are CR, LF. In this case, the offset is advanced by two
characters.
- PCRE2_SUBSTITUTE_OVERFLOW_LENGTH changes what happens when the output
+ PCRE2_SUBSTITUTE_OVERFLOW_LENGTH changes what happens when the output
buffer is too small. The default action is to return PCRE2_ERROR_NOMEM-
- ORY immediately. If this option is set, however, pcre2_substitute()
+ ORY immediately. If this option is set, however, pcre2_substitute()
continues to go through the motions of matching and substituting (with-
- out, of course, writing anything) in order to compute the size of buf-
- fer that is needed. This value is passed back via the outlengthptr
- variable, with the result of the function still being
+ out, of course, writing anything) in order to compute the size of buf-
+ fer that is needed. This value is passed back via the outlengthptr
+ variable, with the result of the function still being
PCRE2_ERROR_NOMEMORY.
- Passing a buffer size of zero is a permitted way of finding out how
- much memory is needed for given substitution. However, this does mean
+ Passing a buffer size of zero is a permitted way of finding out how
+ much memory is needed for given substitution. However, this does mean
that the entire operation is carried out twice. Depending on the appli-
- cation, it may be more efficient to allocate a large buffer and free
- the excess afterwards, instead of using PCRE2_SUBSTITUTE_OVER-
+ cation, it may be more efficient to allocate a large buffer and free
+ the excess afterwards, instead of using PCRE2_SUBSTITUTE_OVER-
FLOW_LENGTH.
- PCRE2_SUBSTITUTE_UNKNOWN_UNSET causes references to capturing groups
- that do not appear in the pattern to be treated as unset groups. This
- option should be used with care, because it means that a typo in a
- group name or number no longer causes the PCRE2_ERROR_NOSUBSTRING
+ PCRE2_SUBSTITUTE_UNKNOWN_UNSET causes references to capturing groups
+ that do not appear in the pattern to be treated as unset groups. This
+ option should be used with care, because it means that a typo in a
+ group name or number no longer causes the PCRE2_ERROR_NOSUBSTRING
error.
- PCRE2_SUBSTITUTE_UNSET_EMPTY causes unset capturing groups (including
+ PCRE2_SUBSTITUTE_UNSET_EMPTY causes unset capturing groups (including
unknown groups when PCRE2_SUBSTITUTE_UNKNOWN_UNSET is set) to be
- treated as empty strings when inserted as described above. If this
- option is not set, an attempt to insert an unset group causes the
- PCRE2_ERROR_UNSET error. This option does not influence the extended
+ treated as empty strings when inserted as described above. If this
+ option is not set, an attempt to insert an unset group causes the
+ PCRE2_ERROR_UNSET error. This option does not influence the extended
substitution syntax described below.
- PCRE2_SUBSTITUTE_EXTENDED causes extra processing to be applied to the
- replacement string. Without this option, only the dollar character is
- special, and only the group insertion forms listed above are valid.
+ PCRE2_SUBSTITUTE_EXTENDED causes extra processing to be applied to the
+ replacement string. Without this option, only the dollar character is
+ special, and only the group insertion forms listed above are valid.
When PCRE2_SUBSTITUTE_EXTENDED is set, two things change:
- Firstly, backslash in a replacement string is interpreted as an escape
+ Firstly, backslash in a replacement string is interpreted as an escape
character. The usual forms such as \n or \x{ddd} can be used to specify
- particular character codes, and backslash followed by any non-alphanu-
- meric character quotes that character. Extended quoting can be coded
+ particular character codes, and backslash followed by any non-alphanu-
+ meric character quotes that character. Extended quoting can be coded
using \Q...\E, exactly as in pattern strings.
- There are also four escape sequences for forcing the case of inserted
- letters. The insertion mechanism has three states: no case forcing,
+ There are also four escape sequences for forcing the case of inserted
+ letters. The insertion mechanism has three states: no case forcing,
force upper case, and force lower case. The escape sequences change the
current state: \U and \L change to upper or lower case forcing, respec-
- tively, and \E (when not terminating a \Q quoted sequence) reverts to
- no case forcing. The sequences \u and \l force the next character (if
- it is a letter) to upper or lower case, respectively, and then the
+ tively, and \E (when not terminating a \Q quoted sequence) reverts to
+ no case forcing. The sequences \u and \l force the next character (if
+ it is a letter) to upper or lower case, respectively, and then the
state automatically reverts to no case forcing. Case forcing applies to
all inserted characters, including those from captured groups and let-
ters within \Q...\E quoted sequences.
Note that case forcing sequences such as \U...\E do not nest. For exam-
- ple, the result of processing "\Uaa\LBB\Ecc\E" is "AAbbcc"; the final
+ ple, the result of processing "\Uaa\LBB\Ecc\E" is "AAbbcc"; the final
\E has no effect.
- The second effect of setting PCRE2_SUBSTITUTE_EXTENDED is to add more
- flexibility to group substitution. The syntax is similar to that used
+ The second effect of setting PCRE2_SUBSTITUTE_EXTENDED is to add more
+ flexibility to group substitution. The syntax is similar to that used
by Bash:
${:-}
${:+:}
- As before, may be a group number or a name. The first form speci-
- fies a default value. If group is set, its value is inserted; if
- not, is expanded and the result inserted. The second form
- specifies strings that are expanded and inserted when group is set
- or unset, respectively. The first form is just a convenient shorthand
+ As before, may be a group number or a name. The first form speci-
+ fies a default value. If group is set, its value is inserted; if
+ not, is expanded and the result inserted. The second form
+ specifies strings that are expanded and inserted when group is set
+ or unset, respectively. The first form is just a convenient shorthand
for
${:+${}:}
- Backslash can be used to escape colons and closing curly brackets in
- the replacement strings. A change of the case forcing state within a
- replacement string remains in force afterwards, as shown in this
+ Backslash can be used to escape colons and closing curly brackets in
+ the replacement strings. A change of the case forcing state within a
+ replacement string remains in force afterwards, as shown in this
pcre2test example:
/(some)?(body)/substitute_extended,replace=${1:+\U:\L}HeLLo
@@ -3216,42 +3224,42 @@ CREATING A NEW STRING WITH SUBSTITUTIONS
somebody
1: HELLO
- The PCRE2_SUBSTITUTE_UNSET_EMPTY option does not affect these extended
- substitutions. However, PCRE2_SUBSTITUTE_UNKNOWN_UNSET does cause
+ The PCRE2_SUBSTITUTE_UNSET_EMPTY option does not affect these extended
+ substitutions. However, PCRE2_SUBSTITUTE_UNKNOWN_UNSET does cause
unknown groups in the extended syntax forms to be treated as unset.
- If successful, pcre2_substitute() returns the number of replacements
+ If successful, pcre2_substitute() returns the number of replacements
that were made. This may be zero if no matches were found, and is never
greater than 1 unless PCRE2_SUBSTITUTE_GLOBAL is set.
In the event of an error, a negative error code is returned. Except for
- PCRE2_ERROR_NOMATCH (which is never returned), errors from
+ PCRE2_ERROR_NOMATCH (which is never returned), errors from
pcre2_match() are passed straight back.
PCRE2_ERROR_NOSUBSTRING is returned for a non-existent substring inser-
tion, unless PCRE2_SUBSTITUTE_UNKNOWN_UNSET is set.
PCRE2_ERROR_UNSET is returned for an unset substring insertion (includ-
- ing an unknown substring when PCRE2_SUBSTITUTE_UNKNOWN_UNSET is set)
+ ing an unknown substring when PCRE2_SUBSTITUTE_UNKNOWN_UNSET is set)
when the simple (non-extended) syntax is used and PCRE2_SUBSTI-
TUTE_UNSET_EMPTY is not set.
- PCRE2_ERROR_NOMEMORY is returned if the output buffer is not big
+ PCRE2_ERROR_NOMEMORY is returned if the output buffer is not big
enough. If the PCRE2_SUBSTITUTE_OVERFLOW_LENGTH option is set, the size
- of buffer that is needed is returned via outlengthptr. Note that this
+ of buffer that is needed is returned via outlengthptr. Note that this
does not happen by default.
- PCRE2_ERROR_BADREPLACEMENT is used for miscellaneous syntax errors in
+ PCRE2_ERROR_BADREPLACEMENT is used for miscellaneous syntax errors in
the replacement string, with more particular errors being
- PCRE2_ERROR_BADREPESCAPE (invalid escape sequence), PCRE2_ERROR_REP-
- MISSINGBRACE (closing curly bracket not found), PCRE2_ERROR_BADSUBSTI-
+ PCRE2_ERROR_BADREPESCAPE (invalid escape sequence), PCRE2_ERROR_REP-
+ MISSINGBRACE (closing curly bracket not found), PCRE2_ERROR_BADSUBSTI-
TUTION (syntax error in extended group substitution), and
- PCRE2_ERROR_BADSUBSPATTERN (the pattern match ended before it started
- or the match started earlier than the current position in the subject,
+ PCRE2_ERROR_BADSUBSPATTERN (the pattern match ended before it started
+ or the match started earlier than the current position in the subject,
which can happen if \K is used in an assertion).
As for all PCRE2 errors, a text message that describes the error can be
- obtained by calling the pcre2_get_error_message() function (see
+ obtained by calling the pcre2_get_error_message() function (see
"Obtaining a textual error message" above).
@@ -3260,56 +3268,56 @@ DUPLICATE SUBPATTERN NAMES
int pcre2_substring_nametable_scan(const pcre2_code *code,
PCRE2_SPTR name, PCRE2_SPTR *first, PCRE2_SPTR *last);
- When a pattern is compiled with the PCRE2_DUPNAMES option, names for
- subpatterns are not required to be unique. Duplicate names are always
- allowed for subpatterns with the same number, created by using the (?|
- feature. Indeed, if such subpatterns are named, they are required to
+ When a pattern is compiled with the PCRE2_DUPNAMES option, names for
+ subpatterns are not required to be unique. Duplicate names are always
+ allowed for subpatterns with the same number, created by using the (?|
+ feature. Indeed, if such subpatterns are named, they are required to
use the same names.
Normally, patterns with duplicate names are such that in any one match,
- only one of the named subpatterns participates. An example is shown in
+ only one of the named subpatterns participates. An example is shown in
the pcre2pattern documentation.
- When duplicates are present, pcre2_substring_copy_byname() and
- pcre2_substring_get_byname() return the first substring corresponding
- to the given name that is set. Only if none are set is
- PCRE2_ERROR_UNSET is returned. The pcre2_substring_number_from_name()
+ When duplicates are present, pcre2_substring_copy_byname() and
+ pcre2_substring_get_byname() return the first substring corresponding
+ to the given name that is set. Only if none are set is
+ PCRE2_ERROR_UNSET is returned. The pcre2_substring_number_from_name()
function returns the error PCRE2_ERROR_NOUNIQUESUBSTRING when there are
duplicate names.
- If you want to get full details of all captured substrings for a given
- name, you must use the pcre2_substring_nametable_scan() function. The
- first argument is the compiled pattern, and the second is the name. If
- the third and fourth arguments are NULL, the function returns a group
+ If you want to get full details of all captured substrings for a given
+ name, you must use the pcre2_substring_nametable_scan() function. The
+ first argument is the compiled pattern, and the second is the name. If
+ the third and fourth arguments are NULL, the function returns a group
number for a unique name, or PCRE2_ERROR_NOUNIQUESUBSTRING otherwise.
When the third and fourth arguments are not NULL, they must be pointers
- to variables that are updated by the function. After it has run, they
+ to variables that are updated by the function. After it has run, they
point to the first and last entries in the name-to-number table for the
- given name, and the function returns the length of each entry in code
- units. In both cases, PCRE2_ERROR_NOSUBSTRING is returned if there are
+ given name, and the function returns the length of each entry in code
+ units. In both cases, PCRE2_ERROR_NOSUBSTRING is returned if there are
no entries for the given name.
The format of the name table is described above in the section entitled
- Information about a pattern. Given all the relevant entries for the
- name, you can extract each of their numbers, and hence the captured
+ Information about a pattern. Given all the relevant entries for the
+ name, you can extract each of their numbers, and hence the captured
data.
FINDING ALL POSSIBLE MATCHES AT ONE POSITION
- The traditional matching function uses a similar algorithm to Perl,
- which stops when it finds the first match at a given point in the sub-
+ The traditional matching function uses a similar algorithm to Perl,
+ which stops when it finds the first match at a given point in the sub-
ject. If you want to find all possible matches, or the longest possible
- match at a given position, consider using the alternative matching
- function (see below) instead. If you cannot use the alternative func-
+ match at a given position, consider using the alternative matching
+ function (see below) instead. If you cannot use the alternative func-
tion, you can kludge it up by making use of the callout facility, which
is described in the pcre2callout documentation.
What you have to do is to insert a callout right at the end of the pat-
- tern. When your callout function is called, extract and save the cur-
- rent matched substring. Then return 1, which forces pcre2_match() to
- backtrack and try other alternatives. Ultimately, when it runs out of
+ tern. When your callout function is called, extract and save the cur-
+ rent matched substring. Then return 1, which forces pcre2_match() to
+ backtrack and try other alternatives. Ultimately, when it runs out of
matches, pcre2_match() will yield PCRE2_ERROR_NOMATCH.
@@ -3321,26 +3329,26 @@ MATCHING A PATTERN: THE ALTERNATIVE FUNCTION
pcre2_match_context *mcontext,
int *workspace, PCRE2_SIZE wscount);
- The function pcre2_dfa_match() is called to match a subject string
- against a compiled pattern, using a matching algorithm that scans the
+ The function pcre2_dfa_match() is called to match a subject string
+ against a compiled pattern, using a matching algorithm that scans the
subject string just once (not counting lookaround assertions), and does
- not backtrack. This has different characteristics to the normal algo-
- rithm, and is not compatible with Perl. Some of the features of PCRE2
- patterns are not supported. Nevertheless, there are times when this
- kind of matching can be useful. For a discussion of the two matching
+ not backtrack. This has different characteristics to the normal algo-
+ rithm, and is not compatible with Perl. Some of the features of PCRE2
+ patterns are not supported. Nevertheless, there are times when this
+ kind of matching can be useful. For a discussion of the two matching
algorithms, and a list of features that pcre2_dfa_match() does not sup-
port, see the pcre2matching documentation.
- The arguments for the pcre2_dfa_match() function are the same as for
+ The arguments for the pcre2_dfa_match() function are the same as for
pcre2_match(), plus two extras. The ovector within the match data block
is used in a different way, and this is described below. The other com-
- mon arguments are used in the same way as for pcre2_match(), so their
+ mon arguments are used in the same way as for pcre2_match(), so their
description is not repeated here.
- The two additional arguments provide workspace for the function. The
- workspace vector should contain at least 20 elements. It is used for
+ The two additional arguments provide workspace for the function. The
+ workspace vector should contain at least 20 elements. It is used for
keeping track of multiple paths through the pattern tree. More
- workspace is needed for patterns and subjects where there are a lot of
+ workspace is needed for patterns and subjects where there are a lot of
potential matches.
Here is an example of a simple call to pcre2_dfa_match():
@@ -3360,45 +3368,45 @@ MATCHING A PATTERN: THE ALTERNATIVE FUNCTION
Option bits for pcre_dfa_match()
- The unused bits of the options argument for pcre2_dfa_match() must be
- zero. The only bits that may be set are PCRE2_ANCHORED, PCRE2_ENDAN-
- CHORED, PCRE2_NOTBOL, PCRE2_NOTEOL, PCRE2_NOTEMPTY,
+ The unused bits of the options argument for pcre2_dfa_match() must be
+ zero. The only bits that may be set are PCRE2_ANCHORED, PCRE2_ENDAN-
+ CHORED, PCRE2_NOTBOL, PCRE2_NOTEOL, PCRE2_NOTEMPTY,
PCRE2_NOTEMPTY_ATSTART, PCRE2_NO_UTF_CHECK, PCRE2_PARTIAL_HARD,
- PCRE2_PARTIAL_SOFT, PCRE2_DFA_SHORTEST, and PCRE2_DFA_RESTART. All but
- the last four of these are exactly the same as for pcre2_match(), so
+ PCRE2_PARTIAL_SOFT, PCRE2_DFA_SHORTEST, and PCRE2_DFA_RESTART. All but
+ the last four of these are exactly the same as for pcre2_match(), so
their description is not repeated here.
PCRE2_PARTIAL_HARD
PCRE2_PARTIAL_SOFT
- These have the same general effect as they do for pcre2_match(), but
- the details are slightly different. When PCRE2_PARTIAL_HARD is set for
- pcre2_dfa_match(), it returns PCRE2_ERROR_PARTIAL if the end of the
+ These have the same general effect as they do for pcre2_match(), but
+ the details are slightly different. When PCRE2_PARTIAL_HARD is set for
+ pcre2_dfa_match(), it returns PCRE2_ERROR_PARTIAL if the end of the
subject is reached and there is still at least one matching possibility
that requires additional characters. This happens even if some complete
- matches have already been found. When PCRE2_PARTIAL_SOFT is set, the
- return code PCRE2_ERROR_NOMATCH is converted into PCRE2_ERROR_PARTIAL
- if the end of the subject is reached, there have been no complete
+ matches have already been found. When PCRE2_PARTIAL_SOFT is set, the
+ return code PCRE2_ERROR_NOMATCH is converted into PCRE2_ERROR_PARTIAL
+ if the end of the subject is reached, there have been no complete
matches, but there is still at least one matching possibility. The por-
- tion of the string that was inspected when the longest partial match
+ tion of the string that was inspected when the longest partial match
was found is set as the first matching string in both cases. There is a
- more detailed discussion of partial and multi-segment matching, with
+ more detailed discussion of partial and multi-segment matching, with
examples, in the pcre2partial documentation.
PCRE2_DFA_SHORTEST
- Setting the PCRE2_DFA_SHORTEST option causes the matching algorithm to
+ Setting the PCRE2_DFA_SHORTEST option causes the matching algorithm to
stop as soon as it has found one match. Because of the way the alterna-
- tive algorithm works, this is necessarily the shortest possible match
+ tive algorithm works, this is necessarily the shortest possible match
at the first possible matching point in the subject string.
PCRE2_DFA_RESTART
- When pcre2_dfa_match() returns a partial match, it is possible to call
+ When pcre2_dfa_match() returns a partial match, it is possible to call
it again, with additional subject characters, and have it continue with
the same match. The PCRE2_DFA_RESTART option requests this action; when
- it is set, the workspace and wscount options must reference the same
- vector as before because data about the match so far is left in them
+ it is set, the workspace and wscount options must reference the same
+ vector as before because data about the match so far is left in them
after a partial match. There is more discussion of this facility in the
pcre2partial documentation.
@@ -3406,8 +3414,8 @@ MATCHING A PATTERN: THE ALTERNATIVE FUNCTION
When pcre2_dfa_match() succeeds, it may have matched more than one sub-
string in the subject. Note, however, that all the matches from one run
- of the function start at the same point in the subject. The shorter
- matches are all initial substrings of the longer matches. For example,
+ of the function start at the same point in the subject. The shorter
+ matches are all initial substrings of the longer matches. For example,
if the pattern
<.*>
@@ -3422,73 +3430,73 @@ MATCHING A PATTERN: THE ALTERNATIVE FUNCTION
- On success, the yield of the function is a number greater than zero,
- which is the number of matched substrings. The offsets of the sub-
- strings are returned in the ovector, and can be extracted by number in
- the same way as for pcre2_match(), but the numbers bear no relation to
- any capturing groups that may exist in the pattern, because DFA match-
+ On success, the yield of the function is a number greater than zero,
+ which is the number of matched substrings. The offsets of the sub-
+ strings are returned in the ovector, and can be extracted by number in
+ the same way as for pcre2_match(), but the numbers bear no relation to
+ any capturing groups that may exist in the pattern, because DFA match-
ing does not support group capture.
- Calls to the convenience functions that extract substrings by name
- return the error PCRE2_ERROR_DFA_UFUNC (unsupported function) if used
+ Calls to the convenience functions that extract substrings by name
+ return the error PCRE2_ERROR_DFA_UFUNC (unsupported function) if used
after a DFA match. The convenience functions that extract substrings by
number never return PCRE2_ERROR_NOSUBSTRING.
- The matched strings are stored in the ovector in reverse order of
- length; that is, the longest matching string is first. If there were
- too many matches to fit into the ovector, the yield of the function is
+ The matched strings are stored in the ovector in reverse order of
+ length; that is, the longest matching string is first. If there were
+ too many matches to fit into the ovector, the yield of the function is
zero, and the vector is filled with the longest matches.
- NOTE: PCRE2's "auto-possessification" optimization usually applies to
- character repeats at the end of a pattern (as well as internally). For
- example, the pattern "a\d+" is compiled as if it were "a\d++". For DFA
- matching, this means that only one possible match is found. If you
- really do want multiple matches in such cases, either use an ungreedy
- repeat such as "a\d+?" or set the PCRE2_NO_AUTO_POSSESS option when
+ NOTE: PCRE2's "auto-possessification" optimization usually applies to
+ character repeats at the end of a pattern (as well as internally). For
+ example, the pattern "a\d+" is compiled as if it were "a\d++". For DFA
+ matching, this means that only one possible match is found. If you
+ really do want multiple matches in such cases, either use an ungreedy
+ repeat such as "a\d+?" or set the PCRE2_NO_AUTO_POSSESS option when
compiling.
Error returns from pcre2_dfa_match()
The pcre2_dfa_match() function returns a negative number when it fails.
- Many of the errors are the same as for pcre2_match(), as described
+ Many of the errors are the same as for pcre2_match(), as described
above. There are in addition the following errors that are specific to
pcre2_dfa_match():
PCRE2_ERROR_DFA_UITEM
- This return is given if pcre2_dfa_match() encounters an item in the
- pattern that it does not support, for instance, the use of \C in a UTF
+ This return is given if pcre2_dfa_match() encounters an item in the
+ pattern that it does not support, for instance, the use of \C in a UTF
mode or a backreference.
PCRE2_ERROR_DFA_UCOND
- This return is given if pcre2_dfa_match() encounters a condition item
+ This return is given if pcre2_dfa_match() encounters a condition item
that uses a backreference for the condition, or a test for recursion in
a specific group. These are not supported.
PCRE2_ERROR_DFA_WSSIZE
- This return is given if pcre2_dfa_match() runs out of space in the
+ This return is given if pcre2_dfa_match() runs out of space in the
workspace vector.
PCRE2_ERROR_DFA_RECURSE
- When a recursive subpattern is processed, the matching function calls
+ When a recursive subpattern is processed, the matching function calls
itself recursively, using private memory for the ovector and workspace.
- This error is given if the internal ovector is not large enough. This
+ This error is given if the internal ovector is not large enough. This
should be extremely rare, as a vector of size 1000 is used.
PCRE2_ERROR_DFA_BADRESTART
- When pcre2_dfa_match() is called with the PCRE2_DFA_RESTART option,
- some plausibility checks are made on the contents of the workspace,
- which should contain data about the previous partial match. If any of
+ When pcre2_dfa_match() is called with the PCRE2_DFA_RESTART option,
+ some plausibility checks are made on the contents of the workspace,
+ which should contain data about the previous partial match. If any of
these checks fail, this error is given.
SEE ALSO
- pcre2build(3), pcre2callout(3), pcre2demo(3), pcre2matching(3),
+ pcre2build(3), pcre2callout(3), pcre2demo(3), pcre2matching(3),
pcre2partial(3), pcre2posix(3), pcre2sample(3), pcre2unicode(3).
@@ -3501,7 +3509,7 @@ AUTHOR
REVISION
- Last updated: 22 June 2018
+ Last updated: 28 June 2018
Copyright (c) 1997-2018 University of Cambridge.
------------------------------------------------------------------------------
@@ -4848,12 +4856,13 @@ CONTROLLING THE JIT STACK
memory allocation functions, or NULL for standard memory allocation).
It returns a pointer to an opaque structure of type pcre2_jit_stack, or
NULL if there is an error. The pcre2_jit_stack_free() function is used
- to free a stack that is no longer needed. (For the technically minded:
- the address space is allocated by mmap or VirtualAlloc.) A maximum
- stack size of 512KiB to 1MiB should be more than enough for any pat-
- tern.
+ to free a stack that is no longer needed. If its argument is NULL, this
+ function returns immediately, without doing anything. (For the techni-
+ cally minded: the address space is allocated by mmap or VirtualAlloc.)
+ A maximum stack size of 512KiB to 1MiB should be more than enough for
+ any pattern.
- The pcre2_jit_stack_assign() function specifies which stack JIT code
+ The pcre2_jit_stack_assign() function specifies which stack JIT code
should use. Its arguments are as follows:
pcre2_match_context *mcontext
@@ -4862,8 +4871,9 @@ CONTROLLING THE JIT STACK
The first argument is a pointer to a match context. When this is subse-
quently passed to a matching function, its information determines which
- JIT stack is used. There are three cases for the values of the other
- two options:
+ JIT stack is used. If this argument is NULL, the function returns imme-
+ diately, without doing anything. There are three cases for the values
+ of the other two options:
(1) If callback is NULL and data is NULL, an internal 32KiB block
on the machine stack is used. This is the default when a match
@@ -5075,8 +5085,8 @@ AUTHOR
REVISION
- Last updated: 31 March 2017
- Copyright (c) 1997-2017 University of Cambridge.
+ Last updated: 28 June 2018
+ Copyright (c) 1997-2018 University of Cambridge.
------------------------------------------------------------------------------
@@ -9659,16 +9669,17 @@ SAVING COMPILED PATTERNS
they can still be used for matching. Their memory must eventually be
freed in the usual way by calling pcre2_code_free(). When you have fin-
ished with the byte stream, it too must be freed by calling pcre2_seri-
- alize_free().
+ alize_free(). If this function is called with a NULL argument, it
+ returns immediately without doing anything.
RE-USING PRECOMPILED PATTERNS
- In order to re-use a set of saved patterns you must first make the
- serialized byte stream available in main memory (for example, by read-
- ing from a file). The management of this memory block is up to the
+ In order to re-use a set of saved patterns you must first make the
+ serialized byte stream available in main memory (for example, by read-
+ ing from a file). The management of this memory block is up to the
application. You can use the pcre2_serialize_get_number_of_codes()
- function to find out how many compiled patterns are in the serialized
+ function to find out how many compiled patterns are in the serialized
data without actually decoding the patterns:
uint8_t *bytes = ;
@@ -9676,10 +9687,10 @@ RE-USING PRECOMPILED PATTERNS
The pcre2_serialize_decode() function reads a byte stream and recreates
the compiled patterns in new memory blocks, setting pointers to them in
- a vector. The first two arguments are a pointer to a suitable vector
- and its length, and the third argument points to a byte stream. The
- final argument is a pointer to a general context, which can be used to
- specify custom memory mangagement functions for the decoded patterns.
+ a vector. The first two arguments are a pointer to a suitable vector
+ and its length, and the third argument points to a byte stream. The
+ final argument is a pointer to a general context, which can be used to
+ specify custom memory mangagement functions for the decoded patterns.
If this argument is NULL, malloc() and free() are used. After deserial-
ization, the byte stream is no longer needed and can be discarded.
@@ -9689,9 +9700,9 @@ RE-USING PRECOMPILED PATTERNS
int32_t number_of_codes =
pcre2_serialize_decode(list_of_codes, 2, bytes, NULL);
- If the vector is not large enough for all the patterns in the byte
- stream, it is filled with those that fit, and the remainder are
- ignored. The yield of the function is the number of decoded patterns,
+ If the vector is not large enough for all the patterns in the byte
+ stream, it is filled with those that fit, and the remainder are
+ ignored. The yield of the function is the number of decoded patterns,
or one of the following negative error codes:
PCRE2_ERROR_BADDATA second argument is zero or less
@@ -9701,24 +9712,24 @@ RE-USING PRECOMPILED PATTERNS
PCRE2_ERROR_MEMORY memory allocation failed
PCRE2_ERROR_NULL first or third argument is NULL
- PCRE2_ERROR_BADMAGIC may mean that the data is corrupt, or that it was
+ PCRE2_ERROR_BADMAGIC may mean that the data is corrupt, or that it was
compiled on a system with different endianness.
Decoded patterns can be used for matching in the usual way, and must be
- freed by calling pcre2_code_free(). However, be aware that there is a
- potential race issue if you are using multiple patterns that were
- decoded from a single byte stream in a multithreaded application. A
+ freed by calling pcre2_code_free(). However, be aware that there is a
+ potential race issue if you are using multiple patterns that were
+ decoded from a single byte stream in a multithreaded application. A
single copy of the character tables is used by all the decoded patterns
and a reference count is used to arrange for its memory to be automati-
- cally freed when the last pattern is freed, but there is no locking on
- this reference count. Therefore, if you want to call pcre2_code_free()
- for these patterns in different threads, you must arrange your own
- locking, and ensure that pcre2_code_free() cannot be called by two
+ cally freed when the last pattern is freed, but there is no locking on
+ this reference count. Therefore, if you want to call pcre2_code_free()
+ for these patterns in different threads, you must arrange your own
+ locking, and ensure that pcre2_code_free() cannot be called by two
threads at the same time.
- If a pattern was processed by pcre2_jit_compile() before being serial-
- ized, the JIT data is discarded and so is no longer available after a
- save/restore cycle. You can, however, process a restored pattern with
+ If a pattern was processed by pcre2_jit_compile() before being serial-
+ ized, the JIT data is discarded and so is no longer available after a
+ save/restore cycle. You can, however, process a restored pattern with
pcre2_jit_compile() if you wish.
diff --git a/doc/pcre2_code_free.3 b/doc/pcre2_code_free.3
index 7376869..9e0ad3c 100644
--- a/doc/pcre2_code_free.3
+++ b/doc/pcre2_code_free.3
@@ -1,4 +1,4 @@
-.TH PCRE2_CODE_FREE 3 "23 March 2017" "PCRE2 10.30"
+.TH PCRE2_CODE_FREE 3 "28 June 2018" "PCRE2 10.32"
.SH NAME
PCRE2 - Perl-compatible regular expressions (revised API)
.SH SYNOPSIS
@@ -13,7 +13,8 @@ PCRE2 - Perl-compatible regular expressions (revised API)
.SH DESCRIPTION
.rs
.sp
-This function frees the memory used for a compiled pattern, including any
+If \fIcode\fP is NULL, this function does nothing. Otherwise, \fIcode\fP must
+point to a compiled pattern. This function frees its memory, including any
memory used by the JIT compiler. If the compiled pattern was created by a call
to \fBpcre2_code_copy_with_tables()\fP, the memory for the character tables is
also freed.
diff --git a/doc/pcre2_compile_context_free.3 b/doc/pcre2_compile_context_free.3
index 0c6d787..e90d744 100644
--- a/doc/pcre2_compile_context_free.3
+++ b/doc/pcre2_compile_context_free.3
@@ -1,4 +1,4 @@
-.TH PCRE2_COMPILE_CONTEXT_FREE 3 "22 October 2014" "PCRE2 10.00"
+.TH PCRE2_COMPILE_CONTEXT_FREE 3 "29 June 2018" "PCRE2 10.32"
.SH NAME
PCRE2 - Perl-compatible regular expressions (revised API)
.SH SYNOPSIS
@@ -15,7 +15,8 @@ PCRE2 - Perl-compatible regular expressions (revised API)
.sp
This function frees the memory occupied by a compile context, using the memory
freeing function from the general context with which it was created, or
-\fBfree()\fP if that was not set.
+\fBfree()\fP if that was not set. If the argument is NULL, the function returns
+immediately without doing anything.
.P
There is a complete description of the PCRE2 native API in the
.\" HREF
diff --git a/doc/pcre2_convert_context_free.3 b/doc/pcre2_convert_context_free.3
index fd5b13c..71e87e1 100644
--- a/doc/pcre2_convert_context_free.3
+++ b/doc/pcre2_convert_context_free.3
@@ -1,4 +1,4 @@
-.TH PCRE2_CONVERT_CONTEXT_FREE 3 "10 July 2017" "PCRE2 10.30"
+.TH PCRE2_CONVERT_CONTEXT_FREE 3 "28 June 2018" "PCRE2 10.32"
.SH NAME
PCRE2 - Perl-compatible regular expressions (revised API)
.SH SYNOPSIS
@@ -16,7 +16,8 @@ PCRE2 - Perl-compatible regular expressions (revised API)
This function is part of an experimental set of pattern conversion functions.
It frees the memory occupied by a convert context, using the memory
freeing function from the general context with which it was created, or
-\fBfree()\fP if that was not set.
+\fBfree()\fP if that was not set. If the argument is NULL, the function returns
+immediately without doing anything.
.P
The pattern conversion functions are described in the
.\" HREF
diff --git a/doc/pcre2_converted_pattern_free.3 b/doc/pcre2_converted_pattern_free.3
index 687e078..0568dbd 100644
--- a/doc/pcre2_converted_pattern_free.3
+++ b/doc/pcre2_converted_pattern_free.3
@@ -1,4 +1,4 @@
-.TH PCRE2_CONVERTED_PATTERN_FREE 3 "11 July 2017" "PCRE2 10.30"
+.TH PCRE2_CONVERTED_PATTERN_FREE 3 "28 June 2018" "PCRE2 10.32"
.SH NAME
PCRE2 - Perl-compatible regular expressions (revised API)
.SH SYNOPSIS
@@ -16,7 +16,8 @@ PCRE2 - Perl-compatible regular expressions (revised API)
This function is part of an experimental set of pattern conversion functions.
It frees the memory occupied by a converted pattern that was obtained by
calling \fBpcre2_pattern_convert()\fP with arguments that caused it to place
-the converted pattern into newly obtained heap memory.
+the converted pattern into newly obtained heap memory. If the argument is NULL,
+the function returns immediately without doing anything.
.P
The pattern conversion functions are described in the
.\" HREF
diff --git a/doc/pcre2_general_context_free.3 b/doc/pcre2_general_context_free.3
index 6285332..df1aa1f 100644
--- a/doc/pcre2_general_context_free.3
+++ b/doc/pcre2_general_context_free.3
@@ -1,4 +1,4 @@
-.TH PCRE2_GENERAL_CONTEXT_FREE 3 "22 October 2014" "PCRE2 10.00"
+.TH PCRE2_GENERAL_CONTEXT_FREE 3 "28 June 2018" "PCRE2 10.32"
.SH NAME
PCRE2 - Perl-compatible regular expressions (revised API)
.SH SYNOPSIS
@@ -14,7 +14,8 @@ PCRE2 - Perl-compatible regular expressions (revised API)
.rs
.sp
This function frees the memory occupied by a general context, using the memory
-freeing function within the context, if set.
+freeing function within the context, if set. If the argument is NULL, the
+function returns immediately without doing anything.
.P
There is a complete description of the PCRE2 native API in the
.\" HREF
diff --git a/doc/pcre2_jit_stack_assign.3 b/doc/pcre2_jit_stack_assign.3
index 04af61f..732d20b 100644
--- a/doc/pcre2_jit_stack_assign.3
+++ b/doc/pcre2_jit_stack_assign.3
@@ -1,4 +1,4 @@
-.TH PCRE2_JIT_STACK_ASSIGN 3 "08 November 2014" "PCRE2 10.0"
+.TH PCRE2_JIT_STACK_ASSIGN 3 "28 June 2018" "PCRE2 10.32"
.SH NAME
PCRE2 - Perl-compatible regular expressions (revised API)
.SH SYNOPSIS
@@ -24,6 +24,9 @@ passed to a matching function. The arguments of this function are:
callback a callback function
callback_data a JIT stack or a value to be passed to the callback
.P
+If \fImcontext\fP is NULL, the function returns immediately, without doing
+anything.
+.P
If \fIcallback\fP is NULL and \fIcallback_data\fP is NULL, an internal 32KiB
block on the machine stack is used.
.P
diff --git a/doc/pcre2_jit_stack_free.3 b/doc/pcre2_jit_stack_free.3
index bfa4f79..0d816a2 100644
--- a/doc/pcre2_jit_stack_free.3
+++ b/doc/pcre2_jit_stack_free.3
@@ -1,4 +1,4 @@
-.TH PCRE2_JIT_STACK_FREE 3 "21 October 2014" "PCRE2 10.00"
+.TH PCRE2_JIT_STACK_FREE 3 "28 June 2018" "PCRE2 10.32"
.SH NAME
PCRE2 - Perl-compatible regular expressions (revised API)
.SH SYNOPSIS
@@ -13,8 +13,9 @@ PCRE2 - Perl-compatible regular expressions (revised API)
.rs
.sp
This function is used to free a JIT stack that was created by
-\fBpcre2_jit_stack_create()\fP when it is no longer needed. For more details,
-see the
+\fBpcre2_jit_stack_create()\fP when it is no longer needed. If the argument is
+NULL, the function returns immediately without doing anything. For more
+details, see the
.\" HREF
\fBpcre2jit\fP
.\"
diff --git a/doc/pcre2_match_context_free.3 b/doc/pcre2_match_context_free.3
index 71b9783..7d19f98 100644
--- a/doc/pcre2_match_context_free.3
+++ b/doc/pcre2_match_context_free.3
@@ -1,4 +1,4 @@
-.TH PCRE2_MATCH_CONTEXT_FREE 3 "22 October 2014" "PCRE2 10.00"
+.TH PCRE2_MATCH_CONTEXT_FREE 3 "28 June 2018" "PCRE2 10.32"
.SH NAME
PCRE2 - Perl-compatible regular expressions (revised API)
.SH SYNOPSIS
@@ -15,7 +15,8 @@ PCRE2 - Perl-compatible regular expressions (revised API)
.sp
This function frees the memory occupied by a match context, using the memory
freeing function from the general context with which it was created, or
-\fBfree()\fP if that was not set.
+\fBfree()\fP if that was not set. If the argument is NULL, the function returns
+immediately without doing anything.
.P
There is a complete description of the PCRE2 native API in the
.\" HREF
diff --git a/doc/pcre2_match_data_free.3 b/doc/pcre2_match_data_free.3
index e22074b..56ed08b 100644
--- a/doc/pcre2_match_data_free.3
+++ b/doc/pcre2_match_data_free.3
@@ -1,4 +1,4 @@
-.TH PCRE2_MATCH_DATA_FREE 3 "25 March 2017" "PCRE2 10.30"
+.TH PCRE2_MATCH_DATA_FREE 3 "28 June 2018" "PCRE2 10.32"
.SH NAME
PCRE2 - Perl-compatible regular expressions (revised API)
.SH SYNOPSIS
@@ -13,9 +13,10 @@ PCRE2 - Perl-compatible regular expressions (revised API)
.SH DESCRIPTION
.rs
.sp
-This function frees the memory occupied by a match data block, using the memory
-freeing function from the general context or compiled pattern with which it was
-created, or \fBfree()\fP if that was not set.
+If \fImatch_data\fP is NULL, this function does nothing. Otherwise,
+\fImatch_data\fP must point to a match data block, which this function frees,
+using the memory freeing function from the general context or compiled pattern
+with which it was created, or \fBfree()\fP if that was not set.
.P
There is a complete description of the PCRE2 native API in the
.\" HREF
diff --git a/doc/pcre2_serialize_free.3 b/doc/pcre2_serialize_free.3
index fd95a1c..e4f1c1a 100644
--- a/doc/pcre2_serialize_free.3
+++ b/doc/pcre2_serialize_free.3
@@ -15,7 +15,8 @@ PCRE2 - Perl-compatible regular expressions (revised API)
.sp
This function frees the memory that was obtained by
\fBpcre2_serialize_encode()\fP to hold a serialized byte stream. The argument
-must point to such a byte stream.
+must point to such a byte stream or be NULL, in which case the function returns
+without doing anything.
.P
There is a complete description of the PCRE2 native API in the
.\" HREF
diff --git a/doc/pcre2_substring_free.3 b/doc/pcre2_substring_free.3
index ca94e78..6d0fd58 100644
--- a/doc/pcre2_substring_free.3
+++ b/doc/pcre2_substring_free.3
@@ -1,4 +1,4 @@
-.TH PCRE2_SUBSTRING_FREE 3 "21 October 2014" "PCRE2 10.00"
+.TH PCRE2_SUBSTRING_FREE 3 "28 June 2018" "PCRE2 10.32"
.SH NAME
PCRE2 - Perl-compatible regular expressions (revised API)
.SH SYNOPSIS
@@ -15,7 +15,7 @@ PCRE2 - Perl-compatible regular expressions (revised API)
This is a convenience function for freeing the memory obtained by a previous
call to \fBpcre2_substring_get_byname()\fP or
\fBpcre2_substring_get_bynumber()\fP. Its only argument is a pointer to the
-string.
+string. If the argument is NULL, the function does nothing.
.P
There is a complete description of the PCRE2 native API in the
.\" HREF
diff --git a/doc/pcre2_substring_list_free.3 b/doc/pcre2_substring_list_free.3
index 4725f9c..f6d7ec2 100644
--- a/doc/pcre2_substring_list_free.3
+++ b/doc/pcre2_substring_list_free.3
@@ -1,4 +1,4 @@
-.TH PCRE2_SUBSTRING_LIST_FREE 3 "21 October 2014" "PCRE2 10.00"
+.TH PCRE2_SUBSTRING_LIST_FREE 3 "28 June 2018" "PCRE2 10.32"
.SH NAME
PCRE2 - Perl-compatible regular expressions (revised API)
.SH SYNOPSIS
@@ -14,7 +14,8 @@ PCRE2 - Perl-compatible regular expressions (revised API)
.sp
This is a convenience function for freeing the store obtained by a previous
call to \fBpcre2substring_list_get()\fP. Its only argument is a pointer to
-the list of string pointers.
+the list of string pointers. If the argument is NULL, the function returns
+immediately, without doing anything.
.P
There is a complete description of the PCRE2 native API in the
.\" HREF
diff --git a/doc/pcre2api.3 b/doc/pcre2api.3
index 9299d3d..e33cef4 100644
--- a/doc/pcre2api.3
+++ b/doc/pcre2api.3
@@ -1,4 +1,4 @@
-.TH PCRE2API 3 "22 June 2018" "PCRE2 10.32"
+.TH PCRE2API 3 "28 June 2018" "PCRE2 10.32"
.SH NAME
PCRE2 - Perl-compatible regular expressions (revised API)
.sp
@@ -453,7 +453,9 @@ been matched by \fBpcre2_match()\fP. They are:
\fBpcre2_substring_number_from_name()\fP
.sp
\fBpcre2_substring_free()\fP and \fBpcre2_substring_list_free()\fP are also
-provided, to free memory used for extracted strings.
+provided, to free memory used for extracted strings. If either of these
+functions is called with a NULL argument, the function returns immediately
+without doing anything.
.P
The function \fBpcre2_substitute()\fP can be called to match a pattern and
return a copy of the subject string with substitutions for parts that were
@@ -666,6 +668,8 @@ The memory used for a general context should be freed by calling:
.B void pcre2_general_context_free(pcre2_general_context *\fIgcontext\fP);
.fi
.sp
+If this function is passed a NULL argument, it function returns immediately
+without doing anything.
.
.
.\" HTML
@@ -1178,6 +1182,8 @@ If the compile context argument \fIccontext\fP is NULL, memory for the compiled
pattern is obtained by calling \fBmalloc()\fP. Otherwise, it is obtained from
the same memory function that was used for the compile context. The caller must
free the memory by calling \fBpcre2_code_free()\fP when it is no longer needed.
+If \fBpcre2_code_free()\fP is called with a NULL argument, it returns
+immediately, without doing anything.
.P
The function \fBpcre2_code_copy()\fP makes a copy of the compiled code in new
memory, using the same memory allocator as was used for the original. However,
@@ -1188,7 +1194,8 @@ below),
.\"
the JIT information cannot be copied (because it is position-dependent).
The new copy can initially be used only for non-JIT matching, though it can be
-passed to \fBpcre2_jit_compile()\fP if required.
+passed to \fBpcre2_jit_compile()\fP if required. If \fBpcre2_code_copy()\fP is
+called with a NULL argument, it returns NULL.
.P
The \fBpcre2_code_copy()\fP function provides a way for individual threads in a
multithreaded application to acquire a private copy of shared compiled code.
@@ -1205,7 +1212,9 @@ there are occasions when a copy of a compiled pattern and the relevant tables
are needed. The \fBpcre2_code_copy_with_tables()\fP provides this facility.
Copies of both the code and the tables are made, with the new code pointing to
the new tables. The memory for the new tables is automatically freed when
-\fBpcre2_code_free()\fP is called for the new copy of the compiled code.
+\fBpcre2_code_free()\fP is called for the new copy of the compiled code. If
+\fBpcre2_code_copy_withy_tables()\fP is called with a NULL argument, it returns
+NULL.
.P
NOTE: When one of the matching functions is called, pointers to the compiled
pattern and the subject string are set in the match data block so that they can
@@ -2333,7 +2342,8 @@ free a compiled pattern or a subject string until after all operations on the
match data block (for that match) have taken place.
.P
When a match data block itself is no longer needed, it should be freed by
-calling \fBpcre2_match_data_free()\fP.
+calling \fBpcre2_match_data_free()\fP. If this function is called with a NULL
+argument, it returns immediately, without doing anything.
.
.
.SH "MATCHING A PATTERN: THE TRADITIONAL FUNCTION"
@@ -3627,6 +3637,6 @@ Cambridge, England.
.rs
.sp
.nf
-Last updated: 22 June 2018
+Last updated: 28 June 2018
Copyright (c) 1997-2018 University of Cambridge.
.fi
diff --git a/doc/pcre2convert.3 b/doc/pcre2convert.3
index 3dadf6e..fc78030 100644
--- a/doc/pcre2convert.3
+++ b/doc/pcre2convert.3
@@ -1,4 +1,4 @@
-.TH PCRE2CONVERT 3 "12 July 2017" "PCRE2 10.30"
+.TH PCRE2CONVERT 3 "28 June 2018" "PCRE2 10.32"
.SH NAME
PCRE2 - Perl-compatible regular expressions (revised API)
.SH "EXPERIMENTAL PATTERN CONVERSION FUNCTIONS"
@@ -83,7 +83,8 @@ If \fBbuffer\fP points to a NULL pointer, an output buffer is obtained using
the allocator in the context or \fBmalloc()\fP if no context is supplied. A
pointer to this buffer is placed in the variable to which \fBbuffer\fP points.
When no longer needed the output buffer must be freed by calling
-\fBpcre2_converted_pattern_free()\fP.
+\fBpcre2_converted_pattern_free()\fP. If this function is called with a NULL
+argument, it returns immediately without doing anything.
.P
If \fBbuffer\fP points to a non-NULL pointer, \fBblength\fP must be set to the
actual length of the buffer provided (in code units).
@@ -158,6 +159,6 @@ Cambridge, England.
.rs
.sp
.nf
-Last updated: 12 July 2017
-Copyright (c) 1997-2017 University of Cambridge.
+Last updated: 28 June 2018
+Copyright (c) 1997-2018 University of Cambridge.
.fi
diff --git a/doc/pcre2jit.3 b/doc/pcre2jit.3
index 2205917..f612faa 100644
--- a/doc/pcre2jit.3
+++ b/doc/pcre2jit.3
@@ -1,4 +1,4 @@
-.TH PCRE2JIT 3 "31 March 2017" "PCRE2 10.30"
+.TH PCRE2JIT 3 "28 June 2018" "PCRE2 10.32"
.SH NAME
PCRE2 - Perl-compatible regular expressions (revised API)
.SH "PCRE2 JUST-IN-TIME COMPILER SUPPORT"
@@ -177,9 +177,10 @@ are a starting size, a maximum size, and a general context (for memory
allocation functions, or NULL for standard memory allocation). It returns a
pointer to an opaque structure of type \fBpcre2_jit_stack\fP, or NULL if there
is an error. The \fBpcre2_jit_stack_free()\fP function is used to free a stack
-that is no longer needed. (For the technically minded: the address space is
-allocated by mmap or VirtualAlloc.) A maximum stack size of 512KiB to 1MiB
-should be more than enough for any pattern.
+that is no longer needed. If its argument is NULL, this function returns
+immediately, without doing anything. (For the technically minded: the address
+space is allocated by mmap or VirtualAlloc.) A maximum stack size of 512KiB to
+1MiB should be more than enough for any pattern.
.P
The \fBpcre2_jit_stack_assign()\fP function specifies which stack JIT code
should use. Its arguments are as follows:
@@ -190,7 +191,8 @@ should use. Its arguments are as follows:
.sp
The first argument is a pointer to a match context. When this is subsequently
passed to a matching function, its information determines which JIT stack is
-used. There are three cases for the values of the other two options:
+used. If this argument is NULL, the function returns immediately, without doing
+anything. There are three cases for the values of the other two options:
.sp
(1) If \fIcallback\fP is NULL and \fIdata\fP is NULL, an internal 32KiB block
on the machine stack is used. This is the default when a match
@@ -410,6 +412,6 @@ Cambridge, England.
.rs
.sp
.nf
-Last updated: 31 March 2017
-Copyright (c) 1997-2017 University of Cambridge.
+Last updated: 28 June 2018
+Copyright (c) 1997-2018 University of Cambridge.
.fi
diff --git a/doc/pcre2serialize.3 b/doc/pcre2serialize.3
index 6caad12..b341e4e 100644
--- a/doc/pcre2serialize.3
+++ b/doc/pcre2serialize.3
@@ -114,7 +114,9 @@ non-binary data, be sure that the file is opened for binary output.
Serializing a set of patterns leaves the original data untouched, so they can
still be used for matching. Their memory must eventually be freed in the usual
way by calling \fBpcre2_code_free()\fP. When you have finished with the byte
-stream, it too must be freed by calling \fBpcre2_serialize_free()\fP.
+stream, it too must be freed by calling \fBpcre2_serialize_free()\fP. If this
+function is called with a NULL argument, it returns immediately without doing
+anything.
.
.
.SH "RE-USING PRECOMPILED PATTERNS"