安全的sprintf是啥？ 是snprintf！！！可对比《基于C语言sprintf函数的深入理解》

https://blog.youkuaiyun.com/unsv29/article/details/83273398 这个链接是《基于C语言sprintf函数的深入理解》

可是不够安全，可能会指针溢出。网上有不少介绍，我也遇到过，所以找了keil里面的函数，找到了

如下：

 

    extern _ARMABI int snprintf(char *__restrict /*s*/, size_t /*n*/,
                                const char *__restrict /*format*/, ...) __attribute__((__nonnull__(3)));
    /*
     * is equivalent to fprintf, except that the argument s specifies an array
     * into which the generated output is to be written, rather than to a
     * stream. The argument n specifies the size of the output array, so as to
     * avoid overflowing the buffer.
     * A null character is written at the end of the characters written, even
     * if the formatting was not completed; it is not counted as part of the
     * returned sum. At most n characters of the output buffer are used,
     * _including_ the null character.
     * Returns: the number of characters that would have been written to the
     *          array, not counting the terminating null character, if the
     *          array had been big enough. So if the return is >=0 and <n, then
     *          the entire string was successfully formatted; if the return is
     *          >=n, the string was truncated (but there is still a null char
     *          at the end of what was written); if the return is <0, there was
     *          an error.
     */

这个函数不错。所以得将程序中的sprintf改为snprintf