PCRE2\_DFA\_MATCH(3) Library Functions Manual PCRE2\_DFA\_MATCH(3)

# [NAME](#NAME)

PCRE2 - Perl-compatible regular expressions (revised API)

# [SYNOPSIS](#SYNOPSIS)

**#include <pcre2.h>**

```
int pcre2_dfa_match(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,
  int *workspace, PCRE2_SIZE wscount);
```

# [DESCRIPTION](#DESCRIPTION)

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 *not* Perl-compatible (the Perl-compatible matching function is **pcre2\_match()**). The arguments for this function 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, for results  
*mcontext* Points to a match context, or is NULL  
*workspace* Points to a vector of ints used as working space  
*wscount* Number of elements in the vector

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 **pcre2\_match\_data\_create\_from\_pattern()** to create the match data block is therefore not advisable when using this function.

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 *length* and *startoffset* values are code units, not characters. The options are:

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  
PCRE2\_NOTEMPTY\_ATSTART An empty string at the start of the subject  
is not a valid match  
PCRE2\_NO\_UTF\_CHECK Do not check the subject for UTF  
validity (only relevant if PCRE2\_UTF  
was set at compile time)  
PCRE2\_PARTIAL\_HARD Return PCRE2\_ERROR\_PARTIAL for a partial  
match even if there is a full match  
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

There are restrictions on what may appear in a pattern when using this matching function. Details are given in the **pcre2matching** documentation. For details of partial matching, see the **pcre2partial** page. 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.

31 August 2021 PCRE2 10.49

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Document: pcre2_dfa_match(3) from pcre2 10.49-r2 (Chainguard OS)
Source: https://github.com/PCRE2Project/pcre2.git