NAME¶

PCRE - Perl-compatible regular expressions

SYNOPSIS¶

#include <pcre.h>

int pcre_exec(const pcre *code, const pcre_extra *extra, const char *subject, int length, int startoffset, int options, int *ovector, int ovecsize);

DESCRIPTION¶

This function matches a compiled regular expression against a given subject string, using a matching algorithm that is similar to Perl's. It returns offsets to captured substrings. Its arguments are:

code Points to the compiled pattern
extra Points to an associated pcre_extra structure,
or is NULL
subject Points to the subject string
length Length of the subject string, in bytes
startoffset Offset in bytes in the subject at which to
start matching
options Option bits
ovector Points to a vector of ints for result offsets
ovecsize Number of elements in the vector (a multiple of 3)

The options are:

PCRE_ANCHORED Match only at the first position
PCRE_BSR_ANYCRLF \R matches only CR, LF, or CRLF
PCRE_BSR_UNICODE \R matches all Unicode line endings
PCRE_NEWLINE_ANY Recognize any Unicode newline sequence
PCRE_NEWLINE_ANYCRLF Recognize CR, LF, and CRLF as newline sequences
PCRE_NEWLINE_CR Set CR as the newline sequence
PCRE_NEWLINE_CRLF Set CRLF as the newline sequence
PCRE_NEWLINE_LF Set LF as the newline sequence
PCRE_NOTBOL Subject is not the beginning of a line
PCRE_NOTEOL Subject is not the end of a line
PCRE_NOTEMPTY An empty string is not a valid match
PCRE_NO_UTF8_CHECK Do not check the subject for UTF-8
validity (only relevant if PCRE_UTF8
was set at compile time)
PCRE_PARTIAL Return PCRE_ERROR_PARTIAL for a partial match

There are restrictions on what may appear in a pattern when partial matching is requested. For details, see the pcrepartial page.

A pcre_extra structure contains the following fields:

flags Bits indicating which fields are set
study_data Opaque data from pcre_study()
match_limit Limit on internal resource use
match_limit_recursion Limit on internal recursion depth
callout_data Opaque data passed back to callouts
tables Points to character tables or is NULL

The flag bits are PCRE_EXTRA_STUDY_DATA, PCRE_EXTRA_MATCH_LIMIT, PCRE_EXTRA_MATCH_LIMIT_RECURSION, PCRE_EXTRA_CALLOUT_DATA, and PCRE_EXTRA_TABLES.

There is a complete description of the PCRE native API in the pcreapi page and a description of the POSIX API in the pcreposix page.