_CP_extract is equivalent to the result = extract(string, ac.expression, vc.expression, sc.expression) BASIC statement.
int _CP_extract(CPSTR** result, CPSTR* string, int ac.expression, int vc.expression, int sc.expression)
This function returns -1 if an error occurs. The error code is contained in _CP_errno.
/* Prints "a". */ CPSTR * s = _CP_mkstr("a\376b"); _CP_extract(&s,s,1,0,0); _CP_print(s);