pcre2_substring_list_get man page
PCRE2 — Perl-compatible regular expressions (revised API)
int pcre2_substring_list_get(pcre2_match_data *match_data, PCRE2_UCHAR ***listptr, PCRE2_SIZE **lengthsptr);
This is a convenience function for extracting all the captured substrings after a pattern match. It builds a list of pointers to the strings, and (optionally) a second list that contains their lengths (in code units), excluding a terminating zero that is added to each of them. All this is done in a single block of memory that is obtained using the same memory allocation function that was used to get the match data block. The convenience function pcre2_substring_list_free() can be used to free it when it is no longer needed. The arguments are:
match_data The match data block
listptr Where to put a pointer to the list
lengthsptr Where to put a pointer to the lengths, or NULL
A pointer to a list of pointers is put in the variable whose address is in listptr. The list is terminated by a NULL pointer. If lengthsptr is not NULL, a matching list of lengths is created, and its address is placed in lengthsptr. The yield of the function is zero on success or PCRE2_ERROR_NOMEMORY if sufficient memory could not be obtained.
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.