#include <pcre2.h>
void pcre2_match_context_free(pcre2_match_context *mcontext);
This function frees the memory occupied by a match context, using the memory freeing function from the general context with which it was created, or free() if that was not set. If the argument is NULL, the function returns immediately without doing anything.
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.