memcmp函数实现——string.h库函数

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函数实现：

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信息来自RHEL，man page:

MEMCMP(3)                  Linux Programmer's Manual                 MEMCMP(3)

NAME
       memcmp - compare memory areas

SYNOPSIS
       #include <string.h>

       int memcmp(const void *s1, const void *s2, size_t n);

DESCRIPTION
       The  memcmp()  function compares the first n bytes (each interpreted as
       unsigned char) of the memory areas s1 and s2.

RETURN VALUE
       The memcmp() function returns  an  integer  less  than,  equal  to,