pcre2/doc/pcre2_compile.3

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.TH PCRE2_COMPILE 3 "22 April 2022" "PCRE2 10.41"
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.SH NAME
PCRE2 - Perl-compatible regular expressions (revised API)
.SH SYNOPSIS
.rs
.sp
.B #include <pcre2.h>
.PP
.nf
.B pcre2_code *pcre2_compile(PCRE2_SPTR \fIpattern\fP, PCRE2_SIZE \fIlength\fP,
.B " uint32_t \fIoptions\fP, int *\fIerrorcode\fP, PCRE2_SIZE *\fIerroroffset,\fP"
.B " pcre2_compile_context *\fIccontext\fP);"
.fi
.
.SH DESCRIPTION
.rs
.sp
This function compiles a regular expression pattern into an internal form. Its
arguments are:
.sp
\fIpattern\fP A string containing expression to be compiled
\fIlength\fP The length of the string or PCRE2_ZERO_TERMINATED
\fIoptions\fP Option bits
\fIerrorcode\fP Where to put an error code
\fIerroffset\fP Where to put an error offset
\fIccontext\fP Pointer to a compile context or NULL
.sp
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The length of the pattern and any error offset that is returned are in code
units, not characters. A compile context is needed only if you want to provide
custom memory allocation functions, or to provide an external function for
system stack size checking, or to change one or more of these parameters:
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.sp
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What \eR matches (Unicode newlines, or CR, LF, CRLF only);
PCRE2's character tables;
The newline character sequence;
The compile time nested parentheses limit;
The maximum pattern length (in code units) that is allowed.
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The additional options bits (see pcre2_set_compile_extra_options())
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.sp
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The option bits are:
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.sp
PCRE2_ANCHORED Force pattern anchoring
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PCRE2_ALLOW_EMPTY_CLASS Allow empty classes
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PCRE2_ALT_BSUX Alternative handling of \eu, \eU, and \ex
PCRE2_ALT_CIRCUMFLEX Alternative handling of ^ in multiline mode
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PCRE2_ALT_VERBNAMES Process backslashes in verb names
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PCRE2_AUTO_CALLOUT Compile automatic callouts
PCRE2_CASELESS Do caseless matching
PCRE2_DOLLAR_ENDONLY $ not to match newline at end
PCRE2_DOTALL . matches anything including NL
PCRE2_DUPNAMES Allow duplicate names for subpatterns
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PCRE2_ENDANCHORED Pattern can match only at end of subject
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PCRE2_EXTENDED Ignore white space and # comments
PCRE2_FIRSTLINE Force matching to be before newline
PCRE2_LITERAL Pattern characters are all literal
PCRE2_MATCH_INVALID_UTF Enable support for matching invalid UTF
PCRE2_MATCH_UNSET_BACKREF Match unset backreferences
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PCRE2_MULTILINE ^ and $ match newlines within data
PCRE2_NEVER_BACKSLASH_C Lock out the use of \eC in patterns
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PCRE2_NEVER_UCP Lock out PCRE2_UCP, e.g. via (*UCP)
PCRE2_NEVER_UTF Lock out PCRE2_UTF, e.g. via (*UTF)
PCRE2_NO_AUTO_CAPTURE Disable numbered capturing paren-
theses (named ones available)
PCRE2_NO_AUTO_POSSESS Disable auto-possessification
PCRE2_NO_DOTSTAR_ANCHOR Disable automatic anchoring for .*
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PCRE2_NO_START_OPTIMIZE Disable match-time start optimizations
PCRE2_NO_UTF_CHECK Do not check the pattern for UTF validity
(only relevant if PCRE2_UTF is set)
PCRE2_UCP Use Unicode properties for \ed, \ew, etc.
PCRE2_UNGREEDY Invert greediness of quantifiers
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PCRE2_USE_OFFSET_LIMIT Enable offset limit for unanchored matching
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PCRE2_UTF Treat pattern and subjects as UTF strings
.sp
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PCRE2 must be built with Unicode support (the default) in order to use
PCRE2_UTF, PCRE2_UCP and related options.
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.P
Additional options may be set in the compile context via the
.\" HREF
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\fBpcre2_set_compile_extra_options\fP
.\"
function.
.P
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If either of \fIerrorcode\fP or \fIerroroffset\fP is NULL, the function returns
NULL immediately. Otherwise, the yield of this function is a pointer to a
private data structure that contains the compiled pattern, or NULL if an error
was detected. In the error case, a text error message can be obtained by
passing the value returned via the \fIerrorcode\fP argument to the the
\fBpcre2_get_error_message()\fP function. The offset (in code units) where the
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error was encountered is returned via the \fIerroroffset\fP argument.
.P
If there is no error, the value passed via \fIerrorcode\fP returns the message
"no error" if passed to \fBpcre2_get_error_message()\fP, and the value passed
via \fIerroroffset\fP is zero.
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.P
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There is a complete description of the PCRE2 native API, with more detail on
each option, in the
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.\" HREF
\fBpcre2api\fP
.\"
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page, and a description of the POSIX API in the
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.\" HREF
\fBpcre2posix\fP
.\"
page.