strncmp源码，及其在含0x00字符数组中的使用问题

源码

结论，strncmp不能在比较字符数组中同一位置可能均为0x00时使用。

#include <string.h>

int STRNCMP(const char *s1, const char *s2, size_t n)
{
    unsigned char c1 = '\0';
    unsigned char c2 = '\0';
    if (n >= 4)
    {
        size_t n4 = n >> 2;
        do
        {
            c1 = (unsigned char)*s1++;
            c2 = (unsigned char)*s2++;
            if (c1 == '\0' || c1 != c2)
                return c1 - c2;
            c1 = (unsigned char)*s1++;
            c2 = (unsigned char)*s2++;
            if (c1 == '\0' || c1 != c2)
                return c1 - c2;
            c1 = (unsigned char)*s1++;
            c2 = (unsigned char)*s2++;
            if (c1 == '\0' || c1 != c2)
                return c1 - c2;
            c1 = (unsigned char)*s1++;
            c2 = (unsigned char)*s2++;
            if (c1 == '\0' || c1 != c2)
                return c1 - c2;
        } while (--n4 > 0);
        n &= 3;
    }
    while (n > 0)
    {
        c1 = (unsigned char)*s1++;
        c2 = (unsigned char)*s2++;
        if (c1 == '\0' || c1 != c2)
            return c1 - c2;
        n--;
    }
    return c1 - c2;
}

问题出现在执行下面的程序，字符不同但结果为0，找到源码一看便知：当比较的字符均为0x00会以 return 0结束，和字符全部相同结果一致。

int main()
{
    char a[16] = {0xeb, 0x20, 0x1, 0x0, 0x0, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0xbe};
    char b[16] = {0xeb, 0x20, 0x1, 0x0, 0x1, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x1, 0xbe};
    int res = STRNCMP(a, b, 16);
    printf("%d\n", res);

    return 0;
}