c - Undefined reference to memcpy_s -

i'm trying fix undefined reference memcpy_s() error. i've included string.h in file , memcpy() function works okay, , i've tried including memory.h. i'm on x64 windows 7 , using gcc 4.8.1 compile.

#include <stdlib.h> #include <stdio.h> #include <string.h>  void domemcopy(char* buf, size_t buf_size, char* in, int chr) {     memcpy_s(buf, buf_size, in, chr); } 

memory buf has been allocated in main function, calls domemcpy(buf, 64, in, bytes). in string read standard input

exact error cmd terminal:

undefined reference "memcpy_s" collect2.exe: error: ld returned 1 exit status

i've never used this, afaik, need add

#define __stdc_want_lib_ext1__ 1 

before

#include <string.h> 

to use memcpy_s().