C格式化输出64位整数平台差异

在windows平台下：
#include <stdio.h>
#include <stdlib.h>

int main(int argc, char **argv)
{
    int            n, i;
    __int64     res;
    scanf("%d", &n);
    while(n){
            res = 1;
            for(i = 2; i <= n; i++){
                res = res * i;
            }
            break;
    }
    //printf("sizeof long int = %d bytes\n", sizeof(res));

    printf("result = %I64d\n", res);
    exit(0);
}

在linux平台下：
    <<< ... >>>

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

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