c - 引用 char 数组时出现段错误

Question

#include<stdio.h>
int main(void)
{
    char * p= "strings are good";
    printf("%s",*p);
    return 0;
}

有人能告诉我为什么会出现段错误吗？

Answer 1

Could somebody please tell me why I am getting segmentation fault here?

C11: 7.21.6 格式化输入/输出函数:

If a conversion specification is invalid, the behavior is undefined.282) If any argument is not the correct type for the corresponding conversion specification, the behavior is undefined.

3.4.3

1 undefined behavior behavior, upon use of a nonportable or erroneous program construct or of erroneous data, for which this International Standard imposes no requirements.

2 NOTE Possible undefined behavior ranges from ignoring the situation completely with unpredictable results, to behaving during translation or program execution in a documented manner characteristic of the environment (with or without the issuance of a diagnostic message), to terminating a translation or execution (with the issuance of a diagnostic message).

*p 是 char 类型。 %s 需要类型为 char * 的参数。这将调用未定义的行为。在这种情况下，任何事情都可能发生。有时您可能会得到预期的结果，有时则不会。这也可能导致程序崩溃或段错误(这里就是这种情况)。

对于%s，您需要传递字符串/文字的起始地址。

改变

printf("%s",*p);  

到

printf("%s",p);