小编mfj*_*nes的帖子

我正在玩C和scanf功能,并遇到了这个奇怪的错误,我似乎无法弄清楚.给出以下代码:

#include <stdio.h>
#include <stdlib.h>

typedef struct {
  int a;
} sample;

void fn(sample *s) {
  char command;
  scanf("%[abc]", &command);
  printf("Read: %c\n", command);
  printf("In the sample function:, %i\n", s->a);
}

int main() {
  sample *s = malloc(sizeof(sample));
  s->a = 4;

  printf("Before sample function: %i\n", s->a);
  fn(s);
  printf("After sample function: %i\n", s->a);

  return 0;
}

这似乎是错误的.随着输出:

$ ./sample
Before sample function: 4
a
Read: a
In the sample function:, 4
Segmentation fault (core dumped)

我用了gdb并附加了一个watch结构,看来在scanf函数内部,它似乎在"修改"结构体？这很奇怪,因为即使在 …