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@ -91,6 +91,9 @@ in the library.
<tr><td><a href="pcre2_callout_enumerate.html">pcre2_callout_enumerate</a></td> <tr><td><a href="pcre2_callout_enumerate.html">pcre2_callout_enumerate</a></td>
<td>&nbsp;&nbsp;Enumerate callouts in a compiled pattern</td></tr> <td>&nbsp;&nbsp;Enumerate callouts in a compiled pattern</td></tr>
<tr><td><a href="pcre2_code_copy.html">pcre2_code_copy</a></td>
<td>&nbsp;&nbsp;Copy a compiled pattern</td></tr>
<tr><td><a href="pcre2_code_free.html">pcre2_code_free</a></td> <tr><td><a href="pcre2_code_free.html">pcre2_code_free</a></td>
<td>&nbsp;&nbsp;Free a compiled pattern</td></tr> <td>&nbsp;&nbsp;Free a compiled pattern</td></tr>

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@ -0,0 +1,42 @@
<html>
<head>
<title>pcre2_code_copy specification</title>
</head>
<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB">
<h1>pcre2_code_copy man page</h1>
<p>
Return to the <a href="index.html">PCRE2 index page</a>.
</p>
<p>
This page is part of the PCRE2 HTML documentation. It was generated
automatically from the original man page. If there is any nonsense in it,
please consult the man page, in case the conversion went wrong.
<br>
<br><b>
SYNOPSIS
</b><br>
<P>
<b>#include &#60;pcre2.h&#62;</b>
</P>
<P>
<b>pcre2_code *pcre2_code_copy(const pcre2_code *<i>code</i>);</b>
</P>
<br><b>
DESCRIPTION
</b><br>
<P>
This function makes a copy of the memory used for a compiled pattern, excluding
any memory used by the JIT compiler. Without a subsequent call to
<b>pcre2_jit_compile()</b>, the copy can be used only for non-JIT matching. The
yield of the function is NULL if <i>code</i> is NULL or if sufficient memory
cannot be obtained.
</P>
<P>
There is a complete description of the PCRE2 native API in the
<a href="pcre2api.html"><b>pcre2api</b></a>
page and a description of the POSIX API in the
<a href="pcre2posix.html"><b>pcre2posix</b></a>
page.
<p>
Return to the <a href="index.html">PCRE2 index page</a>.
</p>

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@ -290,6 +290,9 @@ document for an overview of all the PCRE2 documentation.
</P> </P>
<br><a name="SEC10" href="#TOC1">PCRE2 NATIVE API AUXILIARY FUNCTIONS</a><br> <br><a name="SEC10" href="#TOC1">PCRE2 NATIVE API AUXILIARY FUNCTIONS</a><br>
<P> <P>
<b>pcre2_code *pcre2_code_copy(const pcre2_code *<i>code</i>);</b>
<br>
<br>
<b>int pcre2_get_error_message(int <i>errorcode</i>, PCRE2_UCHAR *<i>buffer</i>,</b> <b>int pcre2_get_error_message(int <i>errorcode</i>, PCRE2_UCHAR *<i>buffer</i>,</b>
<b> PCRE2_SIZE <i>bufflen</i>);</b> <b> PCRE2_SIZE <i>bufflen</i>);</b>
<br> <br>
@ -455,10 +458,19 @@ return a copy of the subject string with substitutions for parts that were
matched. matched.
</P> </P>
<P> <P>
Functions whose names begin with <b>pcre2_serialize_</b> are used for saving
compiled patterns on disc or elsewhere, and reloading them later.
</P>
<P>
Finally, there are functions for finding out information about a compiled Finally, there are functions for finding out information about a compiled
pattern (<b>pcre2_pattern_info()</b>) and about the configuration with which pattern (<b>pcre2_pattern_info()</b>) and about the configuration with which
PCRE2 was built (<b>pcre2_config()</b>). PCRE2 was built (<b>pcre2_config()</b>).
</P> </P>
<P>
Functions with names ending with <b>_free()</b> are used for freeing memory
blocks of various sorts. In all cases, if one of these functions is called with
a NULL argument, it does nothing.
</P>
<br><a name="SEC13" href="#TOC1">STRING LENGTHS AND OFFSETS</a><br> <br><a name="SEC13" href="#TOC1">STRING LENGTHS AND OFFSETS</a><br>
<P> <P>
The PCRE2 API uses string lengths and offsets into strings of code units in The PCRE2 API uses string lengths and offsets into strings of code units in
@ -516,20 +528,51 @@ time ensuring that multithreaded applications can use it.
There are several different blocks of data that are used to pass information There are several different blocks of data that are used to pass information
between the application and the PCRE2 libraries. between the application and the PCRE2 libraries.
</P> </P>
<br><b>
The compiled pattern
</b><br>
<P> <P>
(1) A pointer to the compiled form of a pattern is returned to the user when A pointer to the compiled form of a pattern is returned to the user when
<b>pcre2_compile()</b> is successful. The data in the compiled pattern is fixed, <b>pcre2_compile()</b> is successful. The data in the compiled pattern is fixed,
and does not change when the pattern is matched. Therefore, it is thread-safe, and does not change when the pattern is matched. Therefore, it is thread-safe,
that is, the same compiled pattern can be used by more than one thread that is, the same compiled pattern can be used by more than one thread
simultaneously. An application can compile all its patterns at the start, simultaneously. For example, an application can compile all its patterns at the
before forking off multiple threads that use them. However, if the just-in-time start, before forking off multiple threads that use them. However, if the
optimization feature is being used, it needs separate memory stack areas for just-in-time optimization feature is being used, it needs separate memory stack
each thread. See the areas for each thread. See the
<a href="pcre2jit.html"><b>pcre2jit</b></a> <a href="pcre2jit.html"><b>pcre2jit</b></a>
documentation for more details. documentation for more details.
</P> </P>
<P> <P>
(2) The next section below introduces the idea of "contexts" in which PCRE2 In a more complicated situation, where patterns are compiled only when they are
first needed, but are still shared between threads, pointers to compiled
patterns must be protected from simultaneous writing by multiple threads, at
least until a pattern has been compiled. The logic can be something like this:
<pre>
Get a read-only (shared) lock (mutex) for pointer
if (pointer == NULL)
{
Get a write (unique) lock for pointer
pointer = pcre2_compile(...
}
Release the lock
Use pointer in pcre2_match()
</pre>
Of course, testing for compilation errors should also be included in the code.
</P>
<P>
If JIT is being used, but the JIT compilation is not being done immediately,
(perhaps waiting to see if the pattern is used often enough) similar logic is
required. JIT compilation updates a pointer within the compiled code block, so
a thread must gain unique write access to the pointer before calling
<b>pcre2_jit_compile()</b>. Alternatively, <b>pcre2_code_copy()</b> can be used
to obtain a private copy of the compiled code.
</P>
<br><b>
Context blocks
</b><br>
<P>
The next main section below introduces the idea of "contexts" in which PCRE2
functions are called. A context is nothing more than a collection of parameters functions are called. A context is nothing more than a collection of parameters
that control the way PCRE2 operates. Grouping a number of parameters together that control the way PCRE2 operates. Grouping a number of parameters together
in a context is a convenient way of passing them to a PCRE2 function without in a context is a convenient way of passing them to a PCRE2 function without
@ -543,11 +586,14 @@ are never changed, the same context can be used by all the threads. However, if
any thread needs to change any value in a context, it must make its own any thread needs to change any value in a context, it must make its own
thread-specific copy. thread-specific copy.
</P> </P>
<br><b>
Match blocks
</b><br>
<P> <P>
(3) The matching functions need a block of memory for working space and for The matching functions need a block of memory for working space and for storing
storing the results of a match. This includes details of what was matched, as the results of a match. This includes details of what was matched, as well as
well as additional information such as the name of a (*MARK) setting. Each additional information such as the name of a (*MARK) setting. Each thread must
thread must provide its own version of this memory. provide its own copy of this memory.
</P> </P>
<br><a name="SEC16" href="#TOC1">PCRE2 CONTEXTS</a><br> <br><a name="SEC16" href="#TOC1">PCRE2 CONTEXTS</a><br>
<P> <P>
@ -1007,14 +1053,33 @@ zero.
<br> <br>
<br> <br>
<b>void pcre2_code_free(pcre2_code *<i>code</i>);</b> <b>void pcre2_code_free(pcre2_code *<i>code</i>);</b>
<br>
<br>
<b>pcre2_code *pcre2_code_copy(const pcre2_code *<i>code</i>);</b>
</P> </P>
<P> <P>
The <b>pcre2_compile()</b> function compiles a pattern into an internal form. The <b>pcre2_compile()</b> function compiles a pattern into an internal form.
The pattern is defined by a pointer to a string of code units and a length, If The pattern is defined by a pointer to a string of code units and a length. If
the pattern is zero-terminated, the length can be specified as 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 PCRE2_ZERO_TERMINATED. The function returns a pointer to a block of memory that
contains the compiled pattern and related data. The caller must free the memory contains the compiled pattern and related data.
by calling <b>pcre2_code_free()</b> when it is no longer needed. </P>
<P>
If the compile context argument <i>ccontext</i> is NULL, memory for the compiled
pattern is obtained by calling <b>malloc()</b>. Otherwise, it is obtained from
the same memory function that was used for the compile context. The caller must
free the memory by calling <b>pcre2_code_free()</b> when it is no longer needed.
</P>
<P>
The function <b>pcre2_code_copy()</b> 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
<a href="#jitcompiling">below),</a>
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 <b>pcre2_jit_compile()</b> if required. The <b>pcre2_code_copy()</b>
function provides a way for individual threads in a multithreaded application
to acquire a private copy of shared compiled code.
</P> </P>
<P> <P>
NOTE: When one of the matching functions is called, pointers to the compiled NOTE: When one of the matching functions is called, pointers to the compiled
@ -1025,16 +1090,12 @@ free a compiled pattern (or a subject string) until after all operations on the
have taken place. have taken place.
</P> </P>
<P> <P>
If the compile context argument <i>ccontext</i> is NULL, memory for the compiled The <i>options</i> argument for <b>pcre2_compile()</b> contains various bit
pattern is obtained by calling <b>malloc()</b>. Otherwise, it is obtained from settings that affect the compilation. It should be zero if no options are
the same memory function that was used for the compile context. required. The available options are described below. Some of them (in
</P> particular, those that are compatible with Perl, but some others as well) can
<P> also be set and unset from within the pattern (see the detailed description in
The <i>options</i> argument contains various bit settings that affect the the
compilation. It should be zero if no options are required. The available
options are described below. Some of them (in particular, those that are
compatible with Perl, but some others as well) can also be set and unset from
within the pattern (see the detailed description in the
<a href="pcre2pattern.html"><b>pcre2pattern</b></a> <a href="pcre2pattern.html"><b>pcre2pattern</b></a>
documentation). documentation).
</P> </P>
@ -1282,8 +1343,8 @@ If this option is set, it disables the use of numbered capturing parentheses in
the pattern. Any opening parenthesis that is not followed by ? behaves as if it the pattern. Any opening parenthesis that is not followed by ? behaves as if it
were followed by ?: but named parentheses can still be used for capturing (and were followed by ?: but named parentheses can still be used for capturing (and
they acquire numbers in the usual way). There is no equivalent of this option they acquire numbers in the usual way). There is no equivalent of this option
in Perl. Note that, if this option is set, references to capturing groups (back in Perl. Note that, if this option is set, references to capturing groups (back
references or recursion/subroutine calls) may only refer to named groups, references or recursion/subroutine calls) may only refer to named groups,
though the reference can be by name or by number. though the reference can be by name or by number.
<pre> <pre>
PCRE2_NO_AUTO_POSSESS PCRE2_NO_AUTO_POSSESS
@ -1433,7 +1494,7 @@ are used for invalid UTF strings. These are the same as given by
<a href="pcre2unicode.html"><b>pcre2unicode</b></a> <a href="pcre2unicode.html"><b>pcre2unicode</b></a>
page. The <b>pcre2_get_error_message()</b> function can be called to obtain a page. The <b>pcre2_get_error_message()</b> function can be called to obtain a
textual error message from any error code. textual error message from any error code.
</P> <a name="jitcompiling"></a></P>
<br><a name="SEC20" href="#TOC1">JUST-IN-TIME (JIT) COMPILATION</a><br> <br><a name="SEC20" href="#TOC1">JUST-IN-TIME (JIT) COMPILATION</a><br>
<P> <P>
<b>int pcre2_jit_compile(pcre2_code *<i>code</i>, uint32_t <i>options</i>);</b> <b>int pcre2_jit_compile(pcre2_code *<i>code</i>, uint32_t <i>options</i>);</b>
@ -3123,7 +3184,7 @@ Cambridge, England.
</P> </P>
<br><a name="SEC40" href="#TOC1">REVISION</a><br> <br><a name="SEC40" href="#TOC1">REVISION</a><br>
<P> <P>
Last updated: 31 January 2016 Last updated: 26 February 2016
<br> <br>
Copyright &copy; 1997-2016 University of Cambridge. Copyright &copy; 1997-2016 University of Cambridge.
<br> <br>

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@ -353,9 +353,10 @@ test files that are also processed by <b>perltest.sh</b>. The <b>#perltest</b>
command helps detect tests that are accidentally put in the wrong file. command helps detect tests that are accidentally put in the wrong file.
<pre> <pre>
#pop [&#60;modifiers&#62;] #pop [&#60;modifiers&#62;]
#popcopy [&#60;modifiers&#62;]
</pre> </pre>
This command is used to manipulate the stack of compiled patterns, as described These commands are used to manipulate the stack of compiled patterns, as
in the section entitled "Saving and restoring compiled patterns" described in the section entitled "Saving and restoring compiled patterns"
<a href="#saverestore">below.</a> <a href="#saverestore">below.</a>
<pre> <pre>
#save &#60;filename&#62; #save &#60;filename&#62;
@ -573,6 +574,7 @@ about the pattern:
posix use the POSIX API posix use the POSIX API
posix_nosub use the POSIX API with REG_NOSUB posix_nosub use the POSIX API with REG_NOSUB
push push compiled pattern onto the stack push push compiled pattern onto the stack
pushcopy push a copy onto the stack
stackguard=&#60;number&#62; test the stackguard feature stackguard=&#60;number&#62; test the stackguard feature
tables=[0|1|2] select internal tables tables=[0|1|2] select internal tables
</pre> </pre>
@ -932,12 +934,16 @@ pushed onto a stack of compiled patterns, and <b>pcre2test</b> expects the next
line to contain a new pattern (or a command) instead of a subject line. This line to contain a new pattern (or a command) instead of a subject line. This
facility is used when saving compiled patterns to a file, as described in the facility is used when saving compiled patterns to a file, as described in the
section entitled "Saving and restoring compiled patterns" section entitled "Saving and restoring compiled patterns"
<a href="#saverestore">below.</a> <a href="#saverestore">below. If <b>pushcopy</b> is used instead of <b>push</b>, a copy of the compiled</a>
The <b>push</b> modifier is incompatible with compilation modifiers such as pattern is stacked, leaving the original as current, ready to match the
<b>global</b> that act at match time. Any that are specified are ignored, with a following input lines. This provides a way of testing the
warning message, except for <b>replace</b>, which causes an error. Note that, <b>pcre2_code_copy()</b> function.
<b>jitverify</b>, which is allowed, does not carry through to any subsequent The <b>push</b> and <b>pushcopy </b> modifiers are incompatible with compilation
matching that uses this pattern. modifiers such as <b>global</b> that act at match time. Any that are specified
are ignored (for the stacked copy), with a warning message, except for
<b>replace</b>, which causes an error. Note that <b>jitverify</b>, which is
allowed, does not carry through to any subsequent matching that uses a stacked
pattern.
<a name="subjectmodifiers"></a></P> <a name="subjectmodifiers"></a></P>
<br><a name="SEC11" href="#TOC1">SUBJECT MODIFIERS</a><br> <br><a name="SEC11" href="#TOC1">SUBJECT MODIFIERS</a><br>
<P> <P>
@ -1530,7 +1536,9 @@ item to be tested. For example:
This output indicates that callout number 0 occurred for a match attempt This output indicates that callout number 0 occurred for a match attempt
starting at the fourth character of the subject string, when the pointer was at starting at the fourth character of the subject string, when the pointer was at
the seventh character, and when the next pattern item was \d. Just the seventh character, and when the next pattern item was \d. Just
one circumflex is output if the start and current positions are the same. one circumflex is output if the start and current positions are the same, or if
the current position precedes the start position, which can happen if the
callout is in a lookbehind assertion.
</P> </P>
<P> <P>
Callouts numbered 255 are assumed to be automatic callouts, inserted as a Callouts numbered 255 are assumed to be automatic callouts, inserted as a
@ -1622,11 +1630,16 @@ can be used to test these functions.
<P> <P>
When a pattern with <b>push</b> modifier is successfully compiled, it is pushed When a pattern with <b>push</b> modifier is successfully compiled, it is pushed
onto a stack of compiled patterns, and <b>pcre2test</b> expects the next line to onto a stack of compiled patterns, and <b>pcre2test</b> expects the next line to
contain a new pattern (or command) instead of a subject line. By this means, a contain a new pattern (or command) instead of a subject line. By contrast,
number of patterns can be compiled and retained. The <b>push</b> modifier is the <b>pushcopy</b> modifier causes a copy of the compiled pattern to be
incompatible with <b>posix</b>, and control modifiers that act at match time are stacked, leaving the original available for immediate matching. By using
ignored (with a message). The <b>jitverify</b> modifier applies only at compile <b>push</b> and/or <b>pushcopy</b>, a number of patterns can be compiled and
time. The command retained. These modifiers are incompatible with <b>posix</b>, and control
modifiers that act at match time are ignored (with a message) for the stacked
patterns. The <b>jitverify</b> modifier applies only at compile time.
</P>
<P>
The command
<pre> <pre>
#save &#60;filename&#62; #save &#60;filename&#62;
</pre> </pre>
@ -1643,7 +1656,8 @@ usual by an empty line or end of file. This command may be followed by a
modifier list containing only modifier list containing only
<a href="#controlmodifiers">control modifiers</a> <a href="#controlmodifiers">control modifiers</a>
that act after a pattern has been compiled. In particular, <b>hex</b>, that act after a pattern has been compiled. In particular, <b>hex</b>,
<b>posix</b>, <b>posix_nosub</b>, and <b>push</b> are not allowed, nor are any <b>posix</b>, <b>posix_nosub</b>, <b>push</b>, and <b>pushcopy</b> are not allowed,
nor are any
<a href="#optionmodifiers">option-setting modifiers.</a> <a href="#optionmodifiers">option-setting modifiers.</a>
The JIT modifiers are, however permitted. Here is an example that saves and The JIT modifiers are, however permitted. Here is an example that saves and
reloads two patterns. reloads two patterns.
@ -1661,6 +1675,11 @@ reloads two patterns.
If <b>jitverify</b> is used with #pop, it does not automatically imply If <b>jitverify</b> is used with #pop, it does not automatically imply
<b>jit</b>, which is different behaviour from when it is used on a pattern. <b>jit</b>, which is different behaviour from when it is used on a pattern.
</P> </P>
<P>
The #popcopy command is analagous to the <b>pushcopy</b> modifier in that it
makes current a copy of the topmost stack pattern, leaving the original still
on the stack.
</P>
<br><a name="SEC19" href="#TOC1">SEE ALSO</a><br> <br><a name="SEC19" href="#TOC1">SEE ALSO</a><br>
<P> <P>
<b>pcre2</b>(3), <b>pcre2api</b>(3), <b>pcre2callout</b>(3), <b>pcre2</b>(3), <b>pcre2api</b>(3), <b>pcre2callout</b>(3),
@ -1678,7 +1697,7 @@ Cambridge, England.
</P> </P>
<br><a name="SEC21" href="#TOC1">REVISION</a><br> <br><a name="SEC21" href="#TOC1">REVISION</a><br>
<P> <P>
Last updated: 31 January 2016 Last updated: 06 February 2016
<br> <br>
Copyright &copy; 1997-2016 University of Cambridge. Copyright &copy; 1997-2016 University of Cambridge.
<br> <br>

503
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@ -377,6 +377,8 @@ PCRE2 NATIVE API SERIALIZATION FUNCTIONS
PCRE2 NATIVE API AUXILIARY FUNCTIONS PCRE2 NATIVE API AUXILIARY FUNCTIONS
pcre2_code *pcre2_code_copy(const pcre2_code *code);
int pcre2_get_error_message(int errorcode, PCRE2_UCHAR *buffer, int pcre2_get_error_message(int errorcode, PCRE2_UCHAR *buffer,
PCRE2_SIZE bufflen); PCRE2_SIZE bufflen);
@ -523,76 +525,113 @@ PCRE2 API OVERVIEW
return a copy of the subject string with substitutions for parts that return a copy of the subject string with substitutions for parts that
were matched. were matched.
Finally, there are functions for finding out information about a com- Functions whose names begin with pcre2_serialize_ are used for saving
piled pattern (pcre2_pattern_info()) and about the configuration with compiled patterns on disc or elsewhere, and reloading them later.
Finally, there are functions for finding out information about a com-
piled pattern (pcre2_pattern_info()) and about the configuration with
which PCRE2 was built (pcre2_config()). which PCRE2 was built (pcre2_config()).
Functions with names ending with _free() are used for freeing memory
blocks of various sorts. In all cases, if one of these functions is
called with a NULL argument, it does nothing.
STRING LENGTHS AND OFFSETS STRING LENGTHS AND OFFSETS
The PCRE2 API uses string lengths and offsets into strings of code The PCRE2 API uses string lengths and offsets into strings of code
units in several places. These values are always of type PCRE2_SIZE, units in several places. These values are always of type PCRE2_SIZE,
which is an unsigned integer type, currently always defined as size_t. which is an unsigned integer type, currently always defined as size_t.
The largest value that can be stored in such a type (that is The largest value that can be stored in such a type (that is
~(PCRE2_SIZE)0) is reserved as a special indicator for zero-terminated ~(PCRE2_SIZE)0) is reserved as a special indicator for zero-terminated
strings and unset offsets. Therefore, the longest string that can be strings and unset offsets. Therefore, the longest string that can be
handled is one less than this maximum. handled is one less than this maximum.
NEWLINES NEWLINES
PCRE2 supports five different conventions for indicating line breaks in PCRE2 supports five different conventions for indicating line breaks in
strings: a single CR (carriage return) character, a single LF (line- strings: a single CR (carriage return) character, a single LF (line-
feed) character, the two-character sequence CRLF, any of the three pre- feed) character, the two-character sequence CRLF, any of the three pre-
ceding, or any Unicode newline sequence. The Unicode newline sequences ceding, or any Unicode newline sequence. The Unicode newline sequences
are the three just mentioned, plus the single characters VT (vertical are the three just mentioned, plus the single characters VT (vertical
tab, U+000B), FF (form feed, U+000C), NEL (next line, U+0085), LS (line tab, U+000B), FF (form feed, U+000C), NEL (next line, U+0085), LS (line
separator, U+2028), and PS (paragraph separator, U+2029). separator, U+2028), and PS (paragraph separator, U+2029).
Each of the first three conventions is used by at least one operating Each of the first three conventions is used by at least one operating
system as its standard newline sequence. When PCRE2 is built, a default system as its standard newline sequence. When PCRE2 is built, a default
can be specified. The default default is LF, which is the Unix stan- can be specified. The default default is LF, which is the Unix stan-
dard. However, the newline convention can be changed by an application dard. However, the newline convention can be changed by an application
when calling pcre2_compile(), or it can be specified by special text at when calling pcre2_compile(), or it can be specified by special text at
the start of the pattern itself; this overrides any other settings. See the start of the pattern itself; this overrides any other settings. See
the pcre2pattern page for details of the special character sequences. the pcre2pattern page for details of the special character sequences.
In the PCRE2 documentation the word "newline" is used to mean "the In the PCRE2 documentation the word "newline" is used to mean "the
character or pair of characters that indicate a line break". The choice character or pair of characters that indicate a line break". The choice
of newline convention affects the handling of the dot, circumflex, and of newline convention affects the handling of the dot, circumflex, and
dollar metacharacters, the handling of #-comments in /x mode, and, when dollar metacharacters, the handling of #-comments in /x mode, and, when
CRLF is a recognized line ending sequence, the match position advance- CRLF is a recognized line ending sequence, the match position advance-
ment for a non-anchored pattern. There is more detail about this in the ment for a non-anchored pattern. There is more detail about this in the
section on pcre2_match() options below. section on pcre2_match() options below.
The choice of newline convention does not affect the interpretation of The choice of newline convention does not affect the interpretation of
the \n or \r escape sequences, nor does it affect what \R matches; this the \n or \r escape sequences, nor does it affect what \R matches; this
has its own separate convention. has its own separate convention.
MULTITHREADING MULTITHREADING
In a multithreaded application it is important to keep thread-specific In a multithreaded application it is important to keep thread-specific
data separate from data that can be shared between threads. The PCRE2 data separate from data that can be shared between threads. The PCRE2
library code itself is thread-safe: it contains no static or global library code itself is thread-safe: it contains no static or global
variables. The API is designed to be fairly simple for non-threaded variables. The API is designed to be fairly simple for non-threaded
applications while at the same time ensuring that multithreaded appli- applications while at the same time ensuring that multithreaded appli-
cations can use it. cations can use it.
There are several different blocks of data that are used to pass infor- There are several different blocks of data that are used to pass infor-
mation between the application and the PCRE2 libraries. mation between the application and the PCRE2 libraries.
(1) A pointer to the compiled form of a pattern is returned to the user The compiled pattern
when pcre2_compile() is successful. The data in the compiled pattern is
fixed, and does not change when the pattern is matched. Therefore, it
is thread-safe, that is, the same compiled pattern can be used by more
than one thread simultaneously. An application can compile all its pat-
terns at the start, before forking off multiple threads that use them.
However, if the just-in-time optimization feature is being used, it
needs separate memory stack areas for each thread. See the pcre2jit
documentation for more details.
(2) The next section below introduces the idea of "contexts" in which A pointer to the compiled form of a pattern is returned to the user
when pcre2_compile() is successful. The data in the compiled pattern is
fixed, and does not change when the pattern is matched. Therefore, it
is thread-safe, that is, the same compiled pattern can be used by more
than one thread simultaneously. For example, an application can compile
all its patterns at the start, before forking off multiple threads that
use them. However, if the just-in-time optimization feature is being
used, it needs separate memory stack areas for each thread. See the
pcre2jit documentation for more details.
In a more complicated situation, where patterns are compiled only when
they are first needed, but are still shared between threads, pointers
to compiled patterns must be protected from simultaneous writing by
multiple threads, at least until a pattern has been compiled. The logic
can be something like this:
Get a read-only (shared) lock (mutex) for pointer
if (pointer == NULL)
{
Get a write (unique) lock for pointer
pointer = pcre2_compile(...
}
Release the lock
Use pointer in pcre2_match()
Of course, testing for compilation errors should also be included in
the code.
If JIT is being used, but the JIT compilation is not being done immedi-
ately, (perhaps waiting to see if the pattern is used often enough)
similar logic is required. JIT compilation updates a pointer within the
compiled code block, so a thread must gain unique write access to the
pointer before calling pcre2_jit_compile(). Alternatively,
pcre2_code_copy() can be used to obtain a private copy of the compiled
code.
Context blocks
The next main section below introduces the idea of "contexts" in which
PCRE2 functions are called. A context is nothing more than a collection PCRE2 functions are called. A context is nothing more than a collection
of parameters that control the way PCRE2 operates. Grouping a number of of parameters that control the way PCRE2 operates. Grouping a number of
parameters together in a context is a convenient way of passing them to parameters together in a context is a convenient way of passing them to
@ -605,44 +644,45 @@ MULTITHREADING
threads. However, if any thread needs to change any value in a context, threads. However, if any thread needs to change any value in a context,
it must make its own thread-specific copy. it must make its own thread-specific copy.
(3) The matching functions need a block of memory for working space and Match blocks
for storing the results of a match. This includes details of what was
The matching functions need a block of memory for working space and for
storing the results of a match. This includes details of what was
matched, as well as additional information such as the name of a matched, as well as additional information such as the name of a
(*MARK) setting. Each thread must provide its own version of this mem- (*MARK) setting. Each thread must provide its own copy of this memory.
ory.
PCRE2 CONTEXTS PCRE2 CONTEXTS
Some PCRE2 functions have a lot of parameters, many of which are used Some PCRE2 functions have a lot of parameters, many of which are used
only by specialist applications, for example, those that use custom only by specialist applications, for example, those that use custom
memory management or non-standard character tables. To keep function memory management or non-standard character tables. To keep function
argument lists at a reasonable size, and at the same time to keep the argument lists at a reasonable size, and at the same time to keep the
API extensible, "uncommon" parameters are passed to certain functions API extensible, "uncommon" parameters are passed to certain functions
in a context instead of directly. A context is just a block of memory in a context instead of directly. A context is just a block of memory
that holds the parameter values. Applications that do not need to that holds the parameter values. Applications that do not need to
adjust any of the context parameters can pass NULL when a context adjust any of the context parameters can pass NULL when a context
pointer is required. pointer is required.
There are three different types of context: a general context that is There are three different types of context: a general context that is
relevant for several PCRE2 operations, a compile-time context, and a relevant for several PCRE2 operations, a compile-time context, and a
match-time context. match-time context.
The general context The general context
At present, this context just contains pointers to (and data for) At present, this context just contains pointers to (and data for)
external memory management functions that are called from several external memory management functions that are called from several
places in the PCRE2 library. The context is named `general' rather than places in the PCRE2 library. The context is named `general' rather than
specifically `memory' because in future other fields may be added. If specifically `memory' because in future other fields may be added. If
you do not want to supply your own custom memory management functions, you do not want to supply your own custom memory management functions,
you do not need to bother with a general context. A general context is you do not need to bother with a general context. A general context is
created by: created by:
pcre2_general_context *pcre2_general_context_create( pcre2_general_context *pcre2_general_context_create(
void *(*private_malloc)(PCRE2_SIZE, void *), void *(*private_malloc)(PCRE2_SIZE, void *),
void (*private_free)(void *, void *), void *memory_data); void (*private_free)(void *, void *), void *memory_data);
The two function pointers specify custom memory management functions, The two function pointers specify custom memory management functions,
whose prototypes are: whose prototypes are:
void *private_malloc(PCRE2_SIZE, void *); void *private_malloc(PCRE2_SIZE, void *);
@ -650,16 +690,16 @@ PCRE2 CONTEXTS
Whenever code in PCRE2 calls these functions, the final argument is the Whenever code in PCRE2 calls these functions, the final argument is the
value of memory_data. Either of the first two arguments of the creation value of memory_data. Either of the first two arguments of the creation
function may be NULL, in which case the system memory management func- function may be NULL, in which case the system memory management func-
tions malloc() and free() are used. (This is not currently useful, as tions malloc() and free() are used. (This is not currently useful, as
there are no other fields in a general context, but in future there there are no other fields in a general context, but in future there
might be.) The private_malloc() function is used (if supplied) to might be.) The private_malloc() function is used (if supplied) to
obtain memory for storing the context, and all three values are saved obtain memory for storing the context, and all three values are saved
as part of the context. as part of the context.
Whenever PCRE2 creates a data block of any kind, the block contains a Whenever PCRE2 creates a data block of any kind, the block contains a
pointer to the free() function that matches the malloc() function that pointer to the free() function that matches the malloc() function that
was used. When the time comes to free the block, this function is was used. When the time comes to free the block, this function is
called. called.
A general context can be copied by calling: A general context can be copied by calling:
@ -674,7 +714,7 @@ PCRE2 CONTEXTS
The compile context The compile context
A compile context is required if you want to change the default values A compile context is required if you want to change the default values
of any of the following compile-time parameters: of any of the following compile-time parameters:
What \R matches (Unicode newlines or CR, LF, CRLF only) What \R matches (Unicode newlines or CR, LF, CRLF only)
@ -684,11 +724,11 @@ PCRE2 CONTEXTS
The maximum length of the pattern string The maximum length of the pattern string
An external function for stack checking An external function for stack checking
A compile context is also required if you are using custom memory man- 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- agement. If none of these apply, just pass NULL as the context argu-
ment of pcre2_compile(). 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: tions:
pcre2_compile_context *pcre2_compile_context_create( pcre2_compile_context *pcre2_compile_context_create(
@ -699,33 +739,33 @@ PCRE2 CONTEXTS
void pcre2_compile_context_free(pcre2_compile_context *ccontext); 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 These can be changed by calling the following functions, which return 0
on success, or PCRE2_ERROR_BADDATA if invalid data is detected. on success, or PCRE2_ERROR_BADDATA if invalid data is detected.
int pcre2_set_bsr(pcre2_compile_context *ccontext, int pcre2_set_bsr(pcre2_compile_context *ccontext,
uint32_t value); uint32_t value);
The value must be PCRE2_BSR_ANYCRLF, to specify that \R matches only 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 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 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(). pcre2_dfa_match().
int pcre2_set_character_tables(pcre2_compile_context *ccontext, int pcre2_set_character_tables(pcre2_compile_context *ccontext,
const unsigned char *tables); 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- only argument is a general context. This function builds a set of char-
acter tables in the current locale. acter tables in the current locale.
int pcre2_set_max_pattern_length(pcre2_compile_context *ccontext, int pcre2_set_max_pattern_length(pcre2_compile_context *ccontext,
PCRE2_SIZE value); PCRE2_SIZE value);
This sets a maximum length, in code units, for the pattern string that This sets a maximum length, in code units, for the pattern string that
is to be compiled. If the pattern is longer, an error is generated. is to be compiled. If the pattern is longer, an error is generated.
This facility is provided so that applications that accept patterns This facility is provided so that applications that accept patterns
from external sources can limit their size. The default is the largest from external sources can limit their size. The default is the largest
number that a PCRE2_SIZE variable can hold, which is effectively unlim- number that a PCRE2_SIZE variable can hold, which is effectively unlim-
ited. ited.
@ -733,38 +773,38 @@ PCRE2 CONTEXTS
uint32_t value); uint32_t value);
This specifies which characters or character sequences are to be recog- 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 return only), PCRE2_NEWLINE_LF (linefeed only), PCRE2_NEWLINE_CRLF (the
two-character sequence CR followed by LF), PCRE2_NEWLINE_ANYCRLF (any two-character sequence CR followed by LF), PCRE2_NEWLINE_ANYCRLF (any
of the above), or PCRE2_NEWLINE_ANY (any Unicode newline sequence). of the above), or PCRE2_NEWLINE_ANY (any Unicode newline sequence).
When a pattern is compiled with the PCRE2_EXTENDED option, the value of When a pattern is compiled with the PCRE2_EXTENDED option, the value of
this parameter affects the recognition of white space and the end of this parameter affects the recognition of white space and the end of
internal comments starting with #. The value is saved with the compiled internal comments starting with #. The value is saved with the compiled
pattern for subsequent use by the JIT compiler and by the two inter- pattern for subsequent use by the JIT compiler and by the two inter-
preted matching functions, pcre2_match() and pcre2_dfa_match(). preted matching functions, pcre2_match() and pcre2_dfa_match().
int pcre2_set_parens_nest_limit(pcre2_compile_context *ccontext, int pcre2_set_parens_nest_limit(pcre2_compile_context *ccontext,
uint32_t value); uint32_t value);
This parameter ajusts the limit, set when PCRE2 is built (default 250), This parameter ajusts the limit, set when PCRE2 is built (default 250),
on the depth of parenthesis nesting in a pattern. This limit stops on the depth of parenthesis nesting in a pattern. This limit stops
rogue patterns using up too much system stack when being compiled. rogue patterns using up too much system stack when being compiled.
int pcre2_set_compile_recursion_guard(pcre2_compile_context *ccontext, int pcre2_set_compile_recursion_guard(pcre2_compile_context *ccontext,
int (*guard_function)(uint32_t, void *), void *user_data); int (*guard_function)(uint32_t, void *), void *user_data);
There is at least one application that runs PCRE2 in threads with very 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 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 all costs. The parenthesis limit above cannot take account of how much
stack is actually available. For a finer control, you can supply a stack is actually available. For a finer control, you can supply a
function that is called whenever pcre2_compile() starts to compile a function that is called whenever pcre2_compile() starts to compile a
parenthesized part of a pattern. This function can check the actual parenthesized part of a pattern. This function can check the actual
stack size (or anything else that it wants to, of course). stack size (or anything else that it wants to, of course).
The first argument to the callout function gives the current depth of 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- 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 ment of pcre2_set_compile_recursion_guard(). The callout function
should return zero if all is well, or non-zero to force an error. should return zero if all is well, or non-zero to force an error.
The match context The match context
@ -778,10 +818,10 @@ PCRE2 CONTEXTS
The limit for calling match() recursively The limit for calling match() recursively
A match context is also required if you are using custom memory manage- A match context is also required if you are using custom memory manage-
ment. If none of these apply, just pass NULL as the context argument ment. If none of these apply, just pass NULL as the context argument
of pcre2_match(), pcre2_dfa_match(), or pcre2_jit_match(). 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: tions:
pcre2_match_context *pcre2_match_context_create( pcre2_match_context *pcre2_match_context_create(
@ -792,7 +832,7 @@ PCRE2 CONTEXTS
void pcre2_match_context_free(pcre2_match_context *mcontext); 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 These can be changed by calling the following functions, which return 0
on success, or PCRE2_ERROR_BADDATA if invalid data is detected. on success, or PCRE2_ERROR_BADDATA if invalid data is detected.
@ -800,96 +840,96 @@ PCRE2 CONTEXTS
int (*callout_function)(pcre2_callout_block *, void *), int (*callout_function)(pcre2_callout_block *, void *),
void *callout_data); void *callout_data);
This sets up a "callout" function, which PCRE2 will call at specified This sets up a "callout" function, which PCRE2 will call at specified
points during a matching operation. Details are given in the pcre2call- points during a matching operation. Details are given in the pcre2call-
out documentation. out documentation.
int pcre2_set_offset_limit(pcre2_match_context *mcontext, int pcre2_set_offset_limit(pcre2_match_context *mcontext,
PCRE2_SIZE value); PCRE2_SIZE value);
The offset_limit parameter limits how far an unanchored search can The offset_limit parameter limits how far an unanchored search can
advance in the subject string. The default value is PCRE2_UNSET. The advance in the subject string. The default value is PCRE2_UNSET. The
pcre2_match() and pcre2_dfa_match() functions return pcre2_match() and pcre2_dfa_match() functions return
PCRE2_ERROR_NOMATCH if a match with a starting point before or at the PCRE2_ERROR_NOMATCH if a match with a starting point before or at the
given offset is not found. For example, if the pattern /abc/ is matched given offset is not found. For example, if the pattern /abc/ is matched
against "123abc" with an offset limit less than 3, the result is 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 PCRE2_ERROR_NO_MATCH. A match can never be found if the startoffset
argument of pcre2_match() or pcre2_dfa_match() is greater than the off- argument of pcre2_match() or pcre2_dfa_match() is greater than the off-
set limit. set limit.
When using this facility, you must set PCRE2_USE_OFFSET_LIMIT when When using this facility, you must set PCRE2_USE_OFFSET_LIMIT when
calling pcre2_compile() so that when JIT is in use, different code can calling pcre2_compile() so that when JIT is in use, different code can
be compiled. If a match is started with a non-default match limit when be compiled. If a match is started with a non-default match limit when
PCRE2_USE_OFFSET_LIMIT is not set, an error is generated. PCRE2_USE_OFFSET_LIMIT is not set, an error is generated.
The offset limit facility can be used to track progress when searching The offset limit facility can be used to track progress when searching
large subject strings. See also the PCRE2_FIRSTLINE option, which large subject strings. See also the PCRE2_FIRSTLINE option, which
requires a match to start within the first line of the subject. If this requires a match to start within the first line of the subject. If this
is set with an offset limit, a match must occur in the first line and is set with an offset limit, a match must occur in the first line and
also within the offset limit. In other words, whichever limit comes also within the offset limit. In other words, whichever limit comes
first is used. first is used.
int pcre2_set_match_limit(pcre2_match_context *mcontext, int pcre2_set_match_limit(pcre2_match_context *mcontext,
uint32_t value); 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 resources when processing patterns that are not going using up too many resources when processing patterns that are not going
to match, but which have a very large number of possibilities in their to match, but which have a very large number of possibilities in their
search trees. The classic example is a pattern that uses nested unlim- search trees. The classic example is a pattern that uses nested unlim-
ited repeats. ited repeats.
Internally, pcre2_match() uses a function called match(), which it Internally, pcre2_match() uses a function called match(), which it
calls repeatedly (sometimes recursively). The limit set by match_limit calls repeatedly (sometimes recursively). The limit set by match_limit
is imposed on the number of times this function is called during a is imposed on the number of times this function is called during a
match, which has the effect of limiting the amount of backtracking that match, which has the effect of limiting the amount of backtracking that
can take place. For patterns that are not anchored, the count restarts can take place. For patterns that are not anchored, the count restarts
from zero for each position in the subject string. This limit is not from zero for each position in the subject string. This limit is not
relevant to pcre2_dfa_match(), which ignores it. relevant to pcre2_dfa_match(), which ignores it.
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 cessed by pcre2_jit_compile(), the way in which matching is executed is
entirely different. However, there is still the possibility of runaway entirely different. However, there is still the possibility of runaway
matching that goes on for a very long time, and so the match_limit 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 value is also used in this case (but in a different way) to limit how
long the matching can continue. long the matching can continue.
The default value for the limit can be set when PCRE2 is built; the 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 default default is 10 million, which handles all but the most extreme
cases. If the limit is exceeded, pcre2_match() returns cases. If the limit is exceeded, pcre2_match() returns
PCRE2_ERROR_MATCHLIMIT. A value for the match limit may also be sup- PCRE2_ERROR_MATCHLIMIT. A value for the match limit may also be sup-
plied by an item at the start of a pattern of the form plied by an item at the start of a pattern of the form
(*LIMIT_MATCH=ddd) (*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() 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. or, if no such limit is set, less than the default.
int pcre2_set_recursion_limit(pcre2_match_context *mcontext, int pcre2_set_recursion_limit(pcre2_match_context *mcontext,
uint32_t value); uint32_t value);
The recursion_limit parameter is similar to match_limit, but instead of The recursion_limit parameter is similar to match_limit, but instead of
limiting the total number of times that match() is called, it limits limiting the total number of times that match() is called, it limits
the depth of recursion. The recursion depth is a smaller number than the depth of recursion. The recursion depth is a smaller number than
the total number of calls, because not all calls to match() are recur- the total number of calls, because not all calls to match() are recur-
sive. This limit is of use only if it is set smaller than match_limit. sive. This limit is of use only if it is set smaller than match_limit.
Limiting the recursion depth limits the amount of system stack that can Limiting the recursion depth limits the amount of system stack that can
be used, or, when PCRE2 has been compiled to use memory on the heap be used, or, when PCRE2 has been compiled to use memory on the heap
instead of the stack, the amount of heap memory that can be used. This instead of the stack, the amount of heap memory that can be used. This
limit is not relevant, and is ignored, when matching is done using JIT limit is not relevant, and is ignored, when matching is done using JIT
compiled code or by the pcre2_dfa_match() function. compiled code or by the pcre2_dfa_match() function.
The default value for recursion_limit can be set when PCRE2 is built; The default value for recursion_limit can be set when PCRE2 is built;
the default default is the same value as the default for match_limit. the default default is the same value as the default for match_limit.
If the limit is exceeded, pcre2_match() returns PCRE2_ERROR_RECURSION- If the limit is exceeded, pcre2_match() returns PCRE2_ERROR_RECURSION-
LIMIT. A value for the recursion limit may also be supplied by an item LIMIT. A value for the recursion limit may also be supplied by an item
at the start of a pattern of the form at the start of a pattern of the form
(*LIMIT_RECURSION=ddd) (*LIMIT_RECURSION=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() 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. or, if no such limit is set, less than the default.
int pcre2_set_recursion_memory_management( int pcre2_set_recursion_memory_management(
@ -898,21 +938,21 @@ PCRE2 CONTEXTS
void (*private_free)(void *, void *), void *memory_data); void (*private_free)(void *, void *), void *memory_data);
This function sets up two additional custom memory management functions This function sets up two additional custom memory management functions
for use by pcre2_match() when PCRE2 is compiled to use the heap for for use by pcre2_match() when PCRE2 is compiled to use the heap for
remembering backtracking data, instead of recursive function calls that remembering backtracking data, instead of recursive function calls that
use the system stack. There is a discussion about PCRE2's stack usage use the system stack. There is a discussion about PCRE2's stack usage
in the pcre2stack documentation. See the pcre2build documentation for in the pcre2stack documentation. See the pcre2build documentation for
details of how to build PCRE2. details of how to build PCRE2.
Using the heap for recursion is a non-standard way of building PCRE2, Using the heap for recursion is a non-standard way of building PCRE2,
for use in environments that have limited stacks. Because of the for use in environments that have limited stacks. Because of the
greater use of memory management, pcre2_match() runs more slowly. Func- greater use of memory management, pcre2_match() runs more slowly. Func-
tions that are different to the general custom memory functions are tions that are different to the general custom memory functions are
provided so that special-purpose external code can be used for this provided so that special-purpose external code can be used for this
case, because the memory blocks are all the same size. The blocks are case, because the memory blocks are all the same size. The blocks are
retained by pcre2_match() until it is about to exit so that they can be retained by pcre2_match() until it is about to exit so that they can be
re-used when possible during the match. In the absence of these func- re-used when possible during the match. In the absence of these func-
tions, the normal custom memory management functions are used, if sup- tions, the normal custom memory management functions are used, if sup-
plied, otherwise the system functions. plied, otherwise the system functions.
@ -920,75 +960,75 @@ CHECKING BUILD-TIME OPTIONS
int pcre2_config(uint32_t what, void *where); int pcre2_config(uint32_t what, void *where);
The function pcre2_config() makes it possible for a PCRE2 client to The function pcre2_config() makes it possible for a PCRE2 client to
discover which optional features have been compiled into the PCRE2 discover which optional features have been compiled into the PCRE2
library. The pcre2build documentation has more details about these library. The pcre2build documentation has more details about these
optional features. optional features.
The first argument for pcre2_config() specifies which information is The first argument for pcre2_config() specifies which information is
required. The second argument is a pointer to memory into which the required. The second argument is a pointer to memory into which the
information is placed. If NULL is passed, the function returns the information is placed. If NULL is passed, the function returns the
amount of memory that is needed for the requested information. For amount of memory that is needed for the requested information. For
calls that return numerical values, the value is in bytes; when calls that return numerical values, the value is in bytes; when
requesting these values, where should point to appropriately aligned requesting these values, where should point to appropriately aligned
memory. For calls that return strings, the required length is given in memory. For calls that return strings, the required length is given in
code units, not counting the terminating zero. code units, not counting the terminating zero.
When requesting information, the returned value from pcre2_config() is When requesting information, the returned value from pcre2_config() is
non-negative on success, or the negative error code PCRE2_ERROR_BADOP- 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- TION if the value in the first argument is not recognized. The follow-
ing information is available: ing information is available:
PCRE2_CONFIG_BSR PCRE2_CONFIG_BSR
The output is a uint32_t integer whose value indicates what character The output is a uint32_t integer whose value indicates what character
sequences the \R escape sequence matches by default. A value of sequences the \R escape sequence matches by default. A value of
PCRE2_BSR_UNICODE means that \R matches any Unicode line ending 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. LF, or CRLF. The default can be overridden when a pattern is compiled.
PCRE2_CONFIG_JIT 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. just-in-time compiling is available; otherwise it is set to zero.
PCRE2_CONFIG_JITTARGET PCRE2_CONFIG_JITTARGET
The where argument should point to a buffer that is at least 48 code 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 units long. (The exact length required can be found by calling
pcre2_config() with where set to NULL.) The buffer is filled with a 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 string that contains the name of the architecture for which the JIT
compiler is configured, for example "x86 32bit (little endian + compiler is configured, for example "x86 32bit (little endian +
unaligned)". If JIT support is not available, PCRE2_ERROR_BADOPTION is unaligned)". If JIT support is not available, PCRE2_ERROR_BADOPTION is
returned, otherwise the number of code units used is returned. This 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. the length of the string, plus one unit for the terminating zero.
PCRE2_CONFIG_LINKSIZE PCRE2_CONFIG_LINKSIZE
The output is a uint32_t integer that contains the number of bytes used The output is a uint32_t integer that contains the number of bytes used
for internal linkage in compiled regular expressions. When PCRE2 is 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 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 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 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 when the 32-bit library is compiled, internal linkages always use 4
bytes, so the configured value is not relevant. bytes, so the configured value is not relevant.
The default value of 2 for the 8-bit and 16-bit libraries is sufficient 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 for all but the most massive patterns, since it allows the size of the
compiled pattern to be up to 64K code units. Larger values allow larger compiled pattern to be up to 64K code units. Larger values allow larger
regular expressions to be compiled by those two libraries, but at the regular expressions to be compiled by those two libraries, but at the
expense of slower matching. expense of slower matching.
PCRE2_CONFIG_MATCHLIMIT PCRE2_CONFIG_MATCHLIMIT
The output is a uint32_t integer that gives the default limit for the The output is a uint32_t integer that gives the default limit for the
number of internal matching function calls in a pcre2_match() execu- number of internal matching function calls in a pcre2_match() execu-
tion. Further details are given with pcre2_match() below. tion. Further details are given with pcre2_match() below.
PCRE2_CONFIG_NEWLINE PCRE2_CONFIG_NEWLINE
The output is a uint32_t integer whose value specifies the default The output is a uint32_t integer whose value specifies the default
character sequence that is recognized as meaning "newline". The values character sequence that is recognized as meaning "newline". The values
are: are:
PCRE2_NEWLINE_CR Carriage return (CR) PCRE2_NEWLINE_CR Carriage return (CR)
@ -997,56 +1037,56 @@ CHECKING BUILD-TIME OPTIONS
PCRE2_NEWLINE_ANY Any Unicode line ending PCRE2_NEWLINE_ANY Any Unicode line ending
PCRE2_NEWLINE_ANYCRLF Any of CR, LF, or CRLF PCRE2_NEWLINE_ANYCRLF Any of CR, LF, or CRLF
The default should normally correspond to the standard sequence for The default should normally correspond to the standard sequence for
your operating system. your operating system.
PCRE2_CONFIG_PARENSLIMIT 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 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 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 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 take into account the stack that may already be used by the calling
application. For finer control over compilation stack usage, see application. For finer control over compilation stack usage, see
pcre2_set_compile_recursion_guard(). pcre2_set_compile_recursion_guard().
PCRE2_CONFIG_RECURSIONLIMIT PCRE2_CONFIG_RECURSIONLIMIT
The output is a uint32_t integer that gives the default limit for the The output is a uint32_t integer that gives the default limit for the
depth of recursion when calling the internal matching function in a depth of recursion when calling the internal matching function in a
pcre2_match() execution. Further details are given with pcre2_match() pcre2_match() execution. Further details are given with pcre2_match()
below. below.
PCRE2_CONFIG_STACKRECURSE PCRE2_CONFIG_STACKRECURSE
The output is a uint32_t integer that is set to one if internal recur- The output is a uint32_t integer that is set to one if internal recur-
sion when running pcre2_match() is implemented by recursive function sion when running pcre2_match() is implemented by recursive function
calls that use the system stack to remember their state. This is the calls that use the system stack to remember their state. This is the
usual way that PCRE2 is compiled. The output is zero if PCRE2 was com- usual way that PCRE2 is compiled. The output is zero if PCRE2 was com-
piled to use blocks of data on the heap instead of recursive function piled to use blocks of data on the heap instead of recursive function
calls. calls.
PCRE2_CONFIG_UNICODE_VERSION PCRE2_CONFIG_UNICODE_VERSION
The where argument should point to a buffer that is at least 24 code 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 units long. (The exact length required can be found by calling
pcre2_config() with where set to NULL.) If PCRE2 has been compiled pcre2_config() with where set to NULL.) If PCRE2 has been compiled
without Unicode support, the buffer is filled with the text "Unicode without Unicode support, the buffer is filled with the text "Unicode
not supported". Otherwise, the Unicode version string (for example, not supported". Otherwise, the Unicode version string (for example,
"8.0.0") is inserted. The number of code units used is returned. This "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. is the length of the string plus one unit for the terminating zero.
PCRE2_CONFIG_UNICODE PCRE2_CONFIG_UNICODE
The output is a uint32_t integer that is set to one if Unicode support 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 is available; otherwise it is set to zero. Unicode support implies UTF
support. support.
PCRE2_CONFIG_VERSION PCRE2_CONFIG_VERSION
The where argument should point to a buffer that is at least 12 code The where argument should point to a buffer that is at least 12 code
units long. (The exact length required can be found by calling 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_config() with where set to NULL.) The buffer is filled with the
PCRE2 version string, zero-terminated. The number of code units used is 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- returned. This is the length of the string plus one unit for the termi-
nating zero. nating zero.
@ -1060,32 +1100,43 @@ COMPILING A PATTERN
void pcre2_code_free(pcre2_code *code); void pcre2_code_free(pcre2_code *code);
The pcre2_compile() function compiles a pattern into an internal form. pcre2_code *pcre2_code_copy(const pcre2_code *code);
The pattern is defined by a pointer to a string of code units and a
length, 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. The caller
must free the memory by calling pcre2_code_free() when it is no longer
needed.
NOTE: When one of the matching functions is called, pointers to the The pcre2_compile() function compiles a pattern into an internal form.
compiled pattern and the subject string are set in the match data block The pattern is defined by a pointer to a string of code units and a
so that they can be referenced by the extraction functions. After run- length. If the pattern is zero-terminated, the length can be specified
ning a match, you must not free a compiled pattern (or a subject as PCRE2_ZERO_TERMINATED. The function returns a pointer to a block of
string) until after all operations on the match data block have taken memory that contains the compiled pattern and related data.
place.
If the compile context argument ccontext is NULL, memory for the com- If the compile context argument ccontext is NULL, memory for the com-
piled pattern is obtained by calling malloc(). Otherwise, it is piled pattern is obtained by calling malloc(). Otherwise, it is
obtained from the same memory function that was used for the compile obtained from the same memory function that was used for the compile
context. context. The caller must free the memory by calling pcre2_code_free()
when it is no longer needed.
The options argument contains various bit settings that affect the com- The function pcre2_code_copy() makes a copy of the compiled code in new
pilation. It should be zero if no options are required. The available memory, using the same memory allocator as was used for the original.
options are described below. Some of them (in particular, those that However, if the code has been processed by the JIT compiler (see
are compatible with Perl, but some others as well) can also be set and below), the JIT information cannot be copied (because it is position-
unset from within the pattern (see the detailed description in the dependent). The new copy can initially be used only for non-JIT match-
pcre2pattern documentation). ing, though it can be passed to pcre2_jit_compile() if required. The
pcre2_code_copy() function provides a way for individual threads in a
multithreaded application to acquire a private copy of shared compiled
code.
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 be referenced by the extraction functions. After run-
ning a match, you must not free a compiled pattern (or a subject
string) until after all operations on the match data block have taken
place.
The options argument for pcre2_compile() contains various bit settings
that affect the compilation. It should be zero if no options are
required. The available options are described below. Some of them (in
particular, those that are compatible with Perl, but some others as
well) can also be set and unset from within the pattern (see the
detailed description in the pcre2pattern documentation).
For those options that can be different in different parts of the pat- For those options that can be different in different parts of the pat-
tern, the contents of the options argument specifies their settings at tern, the contents of the options argument specifies their settings at
@ -3058,7 +3109,7 @@ AUTHOR
REVISION REVISION
Last updated: 31 January 2016 Last updated: 26 February 2016
Copyright (c) 1997-2016 University of Cambridge. Copyright (c) 1997-2016 University of Cambridge.
------------------------------------------------------------------------------ ------------------------------------------------------------------------------

101
doc/pcre2test.txt
View File

@ -296,10 +296,11 @@ COMMAND LINES
wrong file. wrong file.
#pop [<modifiers>] #pop [<modifiers>]
#popcopy [<modifiers>]
This command is used to manipulate the stack of compiled patterns, as These commands are used to manipulate the stack of compiled patterns,
described in the section entitled "Saving and restoring compiled pat- as described in the section entitled "Saving and restoring compiled
terns" below. patterns" below.
#save <filename> #save <filename>
@ -518,6 +519,7 @@ PATTERN MODIFIERS
posix use the POSIX API posix use the POSIX API
posix_nosub use the POSIX API with REG_NOSUB posix_nosub use the POSIX API with REG_NOSUB
push push compiled pattern onto the stack push push compiled pattern onto the stack
pushcopy push a copy onto the stack
stackguard=<number> test the stackguard feature stackguard=<number> test the stackguard feature
tables=[0|1|2] select internal tables tables=[0|1|2] select internal tables
@ -833,11 +835,15 @@ PATTERN MODIFIERS
next line to contain a new pattern (or a command) instead of a subject next line to contain a new pattern (or a command) instead of a subject
line. This facility is used when saving compiled patterns to a file, as line. This facility is used when saving compiled patterns to a file, as
described in the section entitled "Saving and restoring compiled pat- described in the section entitled "Saving and restoring compiled pat-
terns" below. The push modifier is incompatible with compilation modi- terns" below. If pushcopy is used instead of push, a copy of the com-
fiers such as global that act at match time. Any that are specified are piled pattern is stacked, leaving the original as current, ready to
ignored, with a warning message, except for replace, which causes an match the following input lines. This provides a way of testing the
error. Note that, jitverify, which is allowed, does not carry through pcre2_code_copy() function. The push and pushcopy modifiers are
to any subsequent matching that uses this pattern. incompatible with compilation modifiers such as global that act at
match time. Any that are specified are ignored (for the stacked copy),
with a warning message, except for replace, which causes an error. Note
that jitverify, which is allowed, does not carry through to any subse-
quent matching that uses a stacked pattern.
SUBJECT MODIFIERS SUBJECT MODIFIERS
@ -1379,10 +1385,11 @@ CALLOUTS
attempt starting at the fourth character of the subject string, when attempt starting at the fourth character of the subject string, when
the pointer was at the seventh character, and when the next pattern the pointer was at the seventh character, and when the next pattern
item was \d. Just one circumflex is output if the start and current item was \d. Just one circumflex is output if the start and current
positions are the same. positions are the same, or if the current position precedes the start
position, which can happen if the callout is in a lookbehind assertion.
Callouts numbered 255 are assumed to be automatic callouts, inserted as Callouts numbered 255 are assumed to be automatic callouts, inserted as
a result of the /auto_callout pattern modifier. In this case, instead a result of the /auto_callout pattern modifier. In this case, instead
of showing the callout number, the offset in the pattern, preceded by a of showing the callout number, the offset in the pattern, preceded by a
plus, is output. For example: plus, is output. For example:
@ -1396,7 +1403,7 @@ CALLOUTS
0: E* 0: E*
If a pattern contains (*MARK) items, an additional line is output when- If a pattern contains (*MARK) items, an additional line is output when-
ever a change of latest mark is passed to the callout function. For ever a change of latest mark is passed to the callout function. For
example: example:
re> /a(*MARK:X)bc/auto_callout re> /a(*MARK:X)bc/auto_callout
@ -1410,17 +1417,17 @@ CALLOUTS
+12 ^ ^ +12 ^ ^
0: abc 0: abc
The mark changes between matching "a" and "b", but stays the same for The mark changes between matching "a" and "b", but stays the same for
the rest of the match, so nothing more is output. If, as a result of the rest of the match, so nothing more is output. If, as a result of
backtracking, the mark reverts to being unset, the text "<unset>" is backtracking, the mark reverts to being unset, the text "<unset>" is
output. output.
Callouts with string arguments Callouts with string arguments
The output for a callout with a string argument is similar, except that The output for a callout with a string argument is similar, except that
instead of outputting a callout number before the position indicators, instead of outputting a callout number before the position indicators,
the callout string and its offset in the pattern string are output the callout string and its offset in the pattern string are output
before the reflection of the subject string, and the subject string is before the reflection of the subject string, and the subject string is
reflected for each callout. For example: reflected for each callout. For example:
re> /^ab(?C'first')cd(?C"second")ef/ re> /^ab(?C'first')cd(?C"second")ef/
@ -1437,41 +1444,46 @@ CALLOUTS
NON-PRINTING CHARACTERS NON-PRINTING CHARACTERS
When pcre2test is outputting text in the compiled version of a pattern, When pcre2test is outputting text in the compiled version of a pattern,
bytes other than 32-126 are always treated as non-printing characters bytes other than 32-126 are always treated as non-printing characters
and are therefore shown as hex escapes. and are therefore shown as hex escapes.
When pcre2test is outputting text that is a matched part of a subject When pcre2test is outputting text that is a matched part of a subject
string, it behaves in the same way, unless a different locale has been string, it behaves in the same way, unless a different locale has been
set for the pattern (using the /locale modifier). In this case, the set for the pattern (using the /locale modifier). In this case, the
isprint() function is used to distinguish printing and non-printing isprint() function is used to distinguish printing and non-printing
characters. characters.
SAVING AND RESTORING COMPILED PATTERNS SAVING AND RESTORING COMPILED PATTERNS
It is possible to save compiled patterns on disc or elsewhere, and It is possible to save compiled patterns on disc or elsewhere, and
reload them later, subject to a number of restrictions. JIT data cannot reload them later, subject to a number of restrictions. JIT data cannot
be saved. The host on which the patterns are reloaded must be running be saved. The host on which the patterns are reloaded must be running
the same version of PCRE2, with the same code unit width, and must also the same version of PCRE2, with the same code unit width, and must also
have the same endianness, pointer width and PCRE2_SIZE type. Before have the same endianness, pointer width and PCRE2_SIZE type. Before
compiled patterns can be saved they must be serialized, that is, con- compiled patterns can be saved they must be serialized, that is, con-
verted to a stream of bytes. A single byte stream may contain any num- verted to a stream of bytes. A single byte stream may contain any num-
ber of compiled patterns, but they must all use the same character ber of compiled patterns, but they must all use the same character
tables. A single copy of the tables is included in the byte stream (its tables. A single copy of the tables is included in the byte stream (its
size is 1088 bytes). size is 1088 bytes).
The functions whose names begin with pcre2_serialize_ are used for The functions whose names begin with pcre2_serialize_ are used for
serializing and de-serializing. They are described in the pcre2serial- serializing and de-serializing. They are described in the pcre2serial-
ize documentation. In this section we describe the features of ize documentation. In this section we describe the features of
pcre2test that can be used to test these functions. pcre2test that can be used to test these functions.
When a pattern with push modifier is successfully compiled, it is When a pattern with push modifier is successfully compiled, it is
pushed onto a stack of compiled patterns, and pcre2test expects the pushed onto a stack of compiled patterns, and pcre2test expects the
next line to contain a new pattern (or command) instead of a subject next line to contain a new pattern (or command) instead of a subject
line. By this means, a number of patterns can be compiled and retained. line. By contrast, the pushcopy modifier causes a copy of the compiled
The push modifier is incompatible with posix, and control modifiers pattern to be stacked, leaving the original available for immediate
that act at match time are ignored (with a message). The jitverify mod- matching. By using push and/or pushcopy, a number of patterns can be
ifier applies only at compile time. The command compiled and retained. These modifiers are incompatible with posix, and
control modifiers that act at match time are ignored (with a message)
for the stacked patterns. The jitverify modifier applies only at com-
pile time.
The command
#save <filename> #save <filename>
@ -1488,9 +1500,10 @@ SAVING AND RESTORING COMPILED PATTERNS
matched with the pattern, terminated as usual by an empty line or end matched with the pattern, terminated as usual by an empty line or end
of file. This command may be followed by a modifier list containing of file. This command may be followed by a modifier list containing
only control modifiers that act after a pattern has been compiled. In only control modifiers that act after a pattern has been compiled. In
particular, hex, posix, posix_nosub, and push are not allowed, nor are particular, hex, posix, posix_nosub, push, and pushcopy are not
any option-setting modifiers. The JIT modifiers are, however permit- allowed, nor are any option-setting modifiers. The JIT modifiers are,
ted. Here is an example that saves and reloads two patterns. however permitted. Here is an example that saves and reloads two pat-
terns.
/abc/push /abc/push
/xyz/push /xyz/push
@ -1502,9 +1515,13 @@ SAVING AND RESTORING COMPILED PATTERNS
#pop jit,bincode #pop jit,bincode
abc abc
If jitverify is used with #pop, it does not automatically imply jit, If jitverify is used with #pop, it does not automatically imply jit,
which is different behaviour from when it is used on a pattern. which is different behaviour from when it is used on a pattern.
The #popcopy command is analagous to the pushcopy modifier in that it
makes current a copy of the topmost stack pattern, leaving the original
still on the stack.
SEE ALSO SEE ALSO
@ -1521,5 +1538,5 @@ AUTHOR
REVISION REVISION
Last updated: 31 January 2016 Last updated: 06 February 2016
Copyright (c) 1997-2016 University of Cambridge. Copyright (c) 1997-2016 University of Cambridge.