pcre2_substitute man page

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SYNOPSIS

#include <pcre2.h>

int pcre2_substitute(const pcre2_code *code, PCRE2_SPTR subject, PCRE2_SIZE length, PCRE2_SIZE startoffset, uint32_t options, pcre2_match_data *match_data, pcre2_match_context *mcontext, PCRE2_SPTR replacement, PCRE2_SIZE rlength, PCRE2_UCHAR *outputbuffer, PCRE2_SIZE *outlengthptr);

DESCRIPTION

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:

  code          Points to the compiled pattern
  subject       Points to the subject string
  length        Length of the subject string
  startoffset   Offset in the subject at which to start matching
  options       Option bits
  match_data    Points to a match data block, or is NULL
  mcontext      Points to a match context, or is NULL
  replacement   Points to the replacement string
  rlength       Length of the replacement string
  outputbuffer  Points to the output buffer
  outlengthptr  Points to the length of the output buffer

A match data block is needed only if you want to inspect the data from the match that is returned in that block or if PCRE2_SUBSTITUTE_MATCHED is set. A match context is needed only if you want to:

  Set up a callout function
  Set a matching offset limit
  Change the backtracking match limit
  Change the backtracking depth limit
  Set custom memory management in the match context

The length, startoffset and rlength values are code units, not characters, as is the contents of the variable pointed at by outlengthptr, which is updated to the actual length of the new string. The subject and replacement lengths can be given as PCRE2_ZERO_TERMINATED for zero-terminated strings. The options are:

  PCRE2_ANCHORED             Match only at the first position
  PCRE2_ENDANCHORED          Pattern can match only at end of subject
  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
  PCRE2_NOTEMPTY_ATSTART     An empty string at the start of the subject is not a valid match
  PCRE2_NO_JIT               Do not use JIT matching
  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_UNKNOWN_UNSET  Treat unknown group as unset
  PCRE2_SUBSTITUTE_UNSET_EMPTY  Simple unset insert = empty string

If PCRE2_SUBSTITUTE_LITERAL is set, PCRE2_SUBSTITUTE_EXTENDED, PCRE2_SUBSTITUTE_UNKNOWN_UNSET, and PCRE2_SUBSTITUTE_UNSET_EMPTY are ignored.

The function returns the number of substitutions, which may be zero if there are no matches. The result may be greater than one only when PCRE2_SUBSTITUTE_GLOBAL is set. In the event of an error, a negative error code is returned.

There is a complete description of the PCRE2 native API in the pcre2api page and a description of the POSIX API in the pcre2posix page.

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