％z修饰符 – 如果缺少％zd，请尝试％u或％lu

#include <stdio.h>
int main(void)
{
    int n = 0;
    size_t intsize;

    intsize = sizeof (int);
    printf("n = %d, n has %zd bytes; all ints have %zd bytes./n", n, sizeof n, intsize );

    return 0;
}