PCRE2 - Perl-compatible regular expressions (revised API) .rs #include <pcre2.h>

 int pcre2_substring_copy_byname(pcre2_match_data *match_data,  " PCRE2_SPTR name, PCRE2_UCHAR *buffer, PCRE2_SIZE *bufflen);" 

. .rs This is a convenience function for extracting a captured substring, identified by name, into a given buffer. The arguments are: match_data The match data block for the match name Name of the required substring buffer Buffer to receive the string bufflen Length of buffer (code units) The bufflen variable is updated to contain the length of the extracted string, excluding the trailing zero. The yield of the function is zero for success or one of the following error numbers: PCRE2_ERROR_NOSUBSTRING there are no groups of that name PCRE2_ERROR_UNAVAILBLE the ovector was too small for that group PCRE2_ERROR_UNSET the group did not participate in the match PCRE2_ERROR_NOMEMORY the buffer is not big enough If there is more than one group with the given name, the first one that is set is returned. In this situation PCRE2_ERROR_UNSET means that no group with the given name was set.

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