Question

submission.c:112:32: error: '%02d' directive output may be truncated writing between 2 and 3 bytes into a
region of size between 0 and 2 [-Werror=format-truncation=]
 snprintf(strTime, 5, "%02d:%02d", minFormed, secFormed);
                            ^~~~
submission.c:112:26: note: directive argument in the range [-59, 59]     snprintf(strTime, 5, "%02d:%02d", minFormed, secFormed);
                      ^~~~~~~~~~~
submission.c:112:5: note: 'snprintf' output between 6 and 9 bytes into a destination of size 5
 snprintf(strTime, 5, "%02d:%02d", minFormed, secFormed);
 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

我有两个变量minFormed和secFormed，它们都是整数。

通过这种方式，我认为它们每个都不超过2个字节。计时器格式应为“ 00:00”，即5个字节。如何强制secFormed部分只有2个字节？

编辑：对不起，太晚了，忘了显示更多代码

char * getCurrentTime (void) {
    double time = ( overflow_counter * 256.0 + TCNT0 ) * PRESCALE  / FREQ;
    int timePassed = (int)(floor(time));
    int secFormed = timePassed % 60;
    int minFormed = timePassed / 60;
    char strTime[5];
    snprintf(strTime, 5, "%02d:%02d", minFormed, secFormed);
    return strTime;
}

计时器实际上不应超过99:59，因为它是用于可以在几分钟内玩的游戏，因此可以实施某种时间限制。

编辑：将字符串缓冲区更改为6大小后出错

submission.c:109:32: error: '%02d' directive output may be truncated writing between 2 and 3 bytes into a
region of size between 1 and 3 [-Werror=format-truncation=]
 snprintf(strTime, 6, "%02d:%02d", minFormed, secFormed);
                            ^~~~submission.c:109:26: note: directive argument in the range [-59, 59]     snprintf(strTime, 6, "%02d:%02d", minFormed, secFormed);                          ^~~~~~~~~~~
submission.c:109:5: note: 'snprintf' output between 6 and 9 bytes into a destination of size 6
 snprintf(strTime, 6, "%02d:%02d", minFormed, secFormed);
 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Answer 1

在这里我只是猜测，因为您没有提供Minimal, Complete, and Verifiable Example。

似乎您正在传递长度5作为缓冲区大小的参数。那就是缓冲区大小包括字符串终止符。

来自this snprintf (and family) reference：

bufsz-最多可以写入bufsz - 1个字符，加上空终止符

您的字符串是六个字符，包括终止符，因此您需要至少六个字符的缓冲区，并告诉snprintf该大小。

哦，关于范围的注释是因为您使用了 signed 整数，所以范围也包括负数，这意味着多余的空间。您可能应该改用unsigned int和格式"%02u"。

您如何强制大小限制以防止格式截断？

1 个答案: