#include <stdio.h>

int
main (void)
{
    long long a = 0xaaaabbbb;

    printf("sizeof(long long) = %d\n", sizeof(long long));
    printf("a = %I64d\n", a); /* only for windows platform */

   return 0;
}

    <<< ... >>>

    printf("a = %Ld\n", a); /* for GNU */

    printf("a = %lld\n", a); /* for GNU another way */
 
    <<< ... >>>