PCRE2 - Perl-compatible regular expressions (revised API)
#include <pcre2.h>
int
pcre2_substring_length_byname(pcre2_match_data
*match_data,
PCRE2_SPTR name, PCRE2_SIZE
*length);
This function returns the length of a matched substring, identified by name. The arguments are:
match_data
The match data block for the match
name The substring name
length Where to return the length, or NULL
The third argument may be NULL if all you want to know is whether or not a substring is set. The yield is zero on success, or a negative error code otherwise.
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.