Difftime returns an invalid value in MinGW

Question

I am trying to calculate the difference between the two time_t.
but difftimereturns its first parameter instead of the difference!
My code is:

 #include <windows.h>
 #include <stdio.h>
 #include <time.h>
 #include <unistd.h>

 int main(){
     time_t etime_t,now_t;
     double time_diff;
     now_t=1388525484L;
     etime_t=1389338644L;
     time_diff=difftime(now_t,etime_t);
     printf("%f",time_diff);
 }

And he prints:

1388525484.000000

I am compiling with GCC(c MinWG)
What is the problem?

Answer 1

MinGw. difftime . 32- difftime, 64 . , ( 0) . . ,

#define _USE_32BIT_TIME_T 1

time.h

Answer 2

/*my little lab:*/
#include <sys/types.h>
#include <stdio.h
#include <time.h>
#include <unistd.h>
int main(void)
{
 time_t etime_t, now_t;
 struct tm timev_n; 
 struct tm timev_e; 
 struct tm *ptimev_n = &timev_n; 
 struct tm *ptimev_e = &timev_e; 

 double time_diff;
 now_t= 1388525484L;
 etime_t=   1389338644L;
 ptimev_n= gmtime_r(&now_t, ptimev_n );
 ptimev_e= gmtime_r(&etime_t, ptimev_e );
 printf (" now:  %s \n", asctime(ptimev_n)); 
 printf (" end:  %s \n", asctime(ptimev_e)); 
 // time_diff=difftime(now_t,etime_t);
 time_diff=difftime(etime_t, now_t);
 printf("%f \n",time_diff);
 etime_t = (time_t)  time_diff;
 ptimev_e= gmtime_r(&etime_t, ptimev_e );
 printf ("back to the 70 diff:  %s \n", asctime(ptimev_e)); 

 return 1;
 }

:

"  : 31 21:31:24 2013

: 10 07:24:04 2014

813160.000000 70 : 10 09:52:40 1970 " PLS difftime, , unsigned time_t?