c语言 - 错误"Stack around variable was corrupted"

Question

错误"堆栈圆变量位已损坏"，MSVS 2013，C99。为什么它不起作用？如果我分配

NAME[(LENGTH) / CHAR_BIT + 1]

程序将正常工作。

#include <stdio.h>
#include <limits.h>
#define CREATE_BIT_FIELD(NAME, LENGTH) 
    unsigned char NAME[(LENGTH) / CHAR_BIT + ((LENGTH) % CHAR_BIT) ? 1 : 0]
#define SET_BIT(NAME, N) 
    NAME[(N) / CHAR_BIT] |= ((unsigned char)1 << ((N) % CHAR_BIT))
#define CLEAR_BIT(NAME, N) 
    NAME[(N) / CHAR_BIT] &= (UCHAR_MAX - ((unsigned char)1 << ((N) % CHAR_BIT)))
#define IS_SETTED(NAME, N) 
    (NAME[(N) / CHAR_BIT] & ((unsigned char)1 << ((N) % CHAR_BIT)))
int main(void)
{ 
    CREATE_BIT_FIELD(BITS, 16);
    for (int i = 0; i < 16; i++)
        SET_BIT(BITS, i);
    for (int i = 0; i < 16; i++)
        putchar(IS_SETTED(BITS, i) ? '1' : '0');
    getchar();
    return 0;
}

Answer 1

unsigned char NAME[(LENGTH) / CHAR_BIT + ((LENGTH) % CHAR_BIT) ? 1 : 0]

正在评估始终以1添加括号

unsigned char NAME[(LENGTH) / CHAR_BIT + (((LENGTH) % CHAR_BIT) ? 1 : 0)]
                                      /* ^ here                        ^ and here */

否则，它被评估为

((LENGTH) / CHAR_BIT + (((LENGTH) % CHAR_BIT)) ? 1 : 0

这是因为运算符优先级。