pcre2/doc/pcre2_substitute.3

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.TH PCRE2_SUBSTITUTE 3 "22 January 2020" "PCRE2 10.35"
.SH NAME
PCRE2 - Perl-compatible regular expressions (revised API)
.SH SYNOPSIS
.rs
.sp
.B #include <pcre2.h>
.PP
.nf
.B int pcre2_substitute(const pcre2_code *\fIcode\fP, PCRE2_SPTR \fIsubject\fP,
.B " PCRE2_SIZE \fIlength\fP, PCRE2_SIZE \fIstartoffset\fP,"
.B " uint32_t \fIoptions\fP, pcre2_match_data *\fImatch_data\fP,"
.B " pcre2_match_context *\fImcontext\fP, PCRE2_SPTR \fIreplacement\fP,"
.B " PCRE2_SIZE \fIrlength\fP, PCRE2_UCHAR *\fIoutputbuffer\fP,"
.B " PCRE2_SIZE *\fIoutlengthptr\fP);"
.fi
.
.SH DESCRIPTION
.rs
.sp
This function matches a compiled regular expression against a given subject
string, using a matching algorithm that is similar to Perl's. It then makes a
copy of the subject, substituting a replacement string for what was matched.
Its arguments are:
.sp
\fIcode\fP Points to the compiled pattern
\fIsubject\fP Points to the subject string
\fIlength\fP Length of the subject string
\fIstartoffset\fP Offset in the subject at which to start matching
\fIoptions\fP Option bits
\fImatch_data\fP Points to a match data block, or is NULL
\fImcontext\fP Points to a match context, or is NULL
\fIreplacement\fP Points to the replacement string
\fIrlength\fP Length of the replacement string
\fIoutputbuffer\fP Points to the output buffer
\fIoutlengthptr\fP Points to the length of the output buffer
.sp
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A match data block is needed only if you want to inspect the data from the
final match that is returned in that block or if PCRE2_SUBSTITUTE_MATCHED is
set. A match context is needed only if you want to:
.sp
Set up a callout function
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Set a matching offset limit
Change the backtracking match limit
Change the backtracking depth limit
Set custom memory management in the match context
.sp
The \fIlength\fP, \fIstartoffset\fP and \fIrlength\fP values are code units,
not characters, as is the contents of the variable pointed at by
\fIoutlengthptr\fP. This variable must contain the length of the output buffer
when the function is called. If the function is successful, the value is
changed to the length of the new string, excluding the trailing zero that is
automatically added.
.P
The subject and replacement lengths can be given as PCRE2_ZERO_TERMINATED for
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zero-terminated strings. The options are:
.sp
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PCRE2_ANCHORED Match only at the first position
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PCRE2_ENDANCHORED Pattern can match only at end of subject
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PCRE2_NOTBOL Subject is not the beginning of a line
PCRE2_NOTEOL Subject is not the end of a line
PCRE2_NOTEMPTY An empty string is not a valid match
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.\" JOIN
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PCRE2_NOTEMPTY_ATSTART An empty string at the start of the
subject is not a valid match
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PCRE2_NO_JIT Do not use JIT matching
.\" JOIN
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PCRE2_NO_UTF_CHECK Do not check the subject or replacement
for UTF validity (only relevant if
PCRE2_UTF was set at compile time)
PCRE2_SUBSTITUTE_EXTENDED Do extended replacement processing
PCRE2_SUBSTITUTE_GLOBAL Replace all occurrences in the subject
PCRE2_SUBSTITUTE_LITERAL The replacement string is literal
PCRE2_SUBSTITUTE_MATCHED Use pre-existing match data for 1st match
PCRE2_SUBSTITUTE_OVERFLOW_LENGTH If overflow, compute needed length
PCRE2_SUBSTITUTE_REPLACEMENT_ONLY Return only replacement string(s)
PCRE2_SUBSTITUTE_UNKNOWN_UNSET Treat unknown group as unset
PCRE2_SUBSTITUTE_UNSET_EMPTY Simple unset insert = empty string
.sp
If PCRE2_SUBSTITUTE_LITERAL is set, PCRE2_SUBSTITUTE_EXTENDED,
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PCRE2_SUBSTITUTE_UNKNOWN_UNSET, and PCRE2_SUBSTITUTE_UNSET_EMPTY are ignored.
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.P
If PCRE2_SUBSTITUTE_MATCHED is set, \fImatch_data\fP must be non-zero; its
contents must be the result of a call to \fBpcre2_match()\fP using the same
pattern and subject.
.P
The function returns the number of substitutions, which may be zero if there
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are no matches. The result may be greater than one only when
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PCRE2_SUBSTITUTE_GLOBAL is set. In the event of an error, a negative error code
is returned.
.P
There is a complete description of the PCRE2 native API in the
.\" HREF
\fBpcre2api\fP
.\"
page and a description of the POSIX API in the
.\" HREF
\fBpcre2posix\fP
.\"
page.