linux man page for pcre_get_substring

PCRE_GET_SUBSTRING(3)					     Library Functions Manual					     PCRE_GET_SUBSTRING(3)

NAME
       PCRE - Perl-compatible regular expressions

SYNOPSIS

       #include <pcre.h>

       int pcre_get_substring(const char *subject, int *ovector,
	    int stringcount, int stringnumber,
	    const char **stringptr);

DESCRIPTION

       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  memory  in	which  the substring is placed is obtained by calling pcre_malloc(). The convenience function pcre_free_substring() can be
       used to free it when it is no longer needed. The yield of the function 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 native API in the pcreapi page and a description of the POSIX API in the pcreposix page.

															     PCRE_GET_SUBSTRING(3)