#include <pcre.h>
int pcre_get_stringnumber(const pcre *code, const char *name);
This convenience function finds the number of a named substring capturing parenthesis in a compiled pattern. Its arguments are:
code Compiled
regular expression
name Name whose number is required
The yield of the function is the number of the parenthesis if the name is found, or PCRE_ERROR_NOSUBSTRING otherwise.
There is a complete description of the PCRE native API in the pcreapi page and a description of the POSIX API in the pcreposix page.