pcre2_substring_length_byname - Man Page

#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

The yield is zero on success, or an error code if the substring is not found.

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.