#include <pcre.h>
int pcre_get_substring(const char *subject, int *ovector, int stringcount, int stringnumber, const char **stringptr);
This is a convenience function for extracting a captured substring. The arguments are:
subject Subject that has been successfully matched ovector Offset vector that pcre_exec() used stringcount Value returned by pcre_exec() stringnumber Number of the required substring stringptr Where to put the string pointer
The yield is the length of the substring, PCRE_ERROR_NOMEMORY if sufficient memory could not be obtained, or PCRE_ERROR_NOSUBSTRING if the string number is invalid.
There is a complete description of the PCRE API in the pcreapi page.