github/doc/pcre2_dfa_match.3

.TH PCRE2_DFA_MATCH 3 "28 August 2021" "PCRE2 10.38"
.SH NAME
PCRE2 - Perl-compatible regular expressions (revised API)
.SH SYNOPSIS
.rs
.sp
.B #include <pcre2.h>
.PP
.nf
.B int pcre2_dfa_match(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,"
.B "  int *\fIworkspace\fP, PCRE2_SIZE \fIwscount\fP);"
.fi
.
.SH DESCRIPTION
.rs
.sp
This function matches a compiled regular expression against a given subject
string, using an alternative matching algorithm that scans the subject string
just once (except when processing lookaround assertions). This function is
\fInot\fP Perl-compatible (the Perl-compatible matching function is
\fBpcre2_match()\fP). The arguments for this function 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, for results
  \fImcontext\fP     Points to a match context, or is NULL
  \fIworkspace\fP    Points to a vector of ints used as working space
  \fIwscount\fP      Number of elements in the vector
.sp
The size of output vector needed to contain all the results depends on the
number of simultaneous matches, not on the number of parentheses in the
pattern. Using \fBpcre2_match_data_create_from_pattern()\fP to create the match
data block is therefore not advisable when using this function.
.P
A match context is needed only if you want to set up a callout function or
specify the heap limit or the match or the recursion depth limits. The
\fIlength\fP and \fIstartoffset\fP values are code units, not characters. The
options are:
.sp
  PCRE2_ANCHORED          Match only at the first position
  PCRE2_COPY_MATCHED_SUBJECT
                          On success, make a private subject copy
  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
.\" JOIN
  PCRE2_NOTEMPTY_ATSTART  An empty string at the start of the subject
                           is not a valid match
.\" JOIN
  PCRE2_NO_UTF_CHECK      Do not check the subject for UTF
                           validity (only relevant if PCRE2_UTF
                           was set at compile time)
.\" JOIN
  PCRE2_PARTIAL_HARD      Return PCRE2_ERROR_PARTIAL for a partial
                           match even if there is a full match
.\" JOIN
  PCRE2_PARTIAL_SOFT      Return PCRE2_ERROR_PARTIAL for a partial
                           match if no full matches are found
  PCRE2_DFA_RESTART       Restart after a partial match
  PCRE2_DFA_SHORTEST      Return only the shortest match
.sp
There are restrictions on what may appear in a pattern when using this matching
function. Details are given in the
.\" HREF
\fBpcre2matching\fP
.\"
documentation. For details of partial matching, see the
.\" HREF
\fBpcre2partial\fP
.\"
page. 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.