是否在释放不确定的行为未初始化的指针的结果？ [英] Does freeing an uninitialized pointer result in undefined behavior?

问题描述

如果您有没有错误初始化，指针，尽量释放它，这是将导致不确定的行为？

我爱：

  INT主要（无效）{    字符*串;
    免费（字符串）;    返回0;
}
 

解决方案

  

是否在释放不确定的行为未初始化的指针的结果？

是

然而，腾出一个空指针是明确的。

从C99标准：

  

的免费功能使空间指向 PTR 被释放，也就是进一步提供分配。如果 PTR 是一个空指针时，没有采取行动。否则，如果该参数不匹配由释放calloc ，早期的malloc返回一个指针或
  的realloc 函数，或者如果空间已释放通过调用免费或 realloc的，在行为是未定义

If you have a pointer that is not initialized and, by mistake, try to free it, is this going to result in undefined behavior?

Like:

int main(void){

    char *string;
    free(string);

    return 0;
}

解决方案

Does freeing an uninitialized pointer result in undefined behavior?

Yes.

However, freeing a null pointer is well-defined.

From the C99 standard:

The free function causes the space pointed to by ptr to be deallocated, that is, made available for further allocation. If ptr is a null pointer, no action occurs. Otherwise, if the argument does not match a pointer earlier returned by the calloc, malloc, or realloc function, or if the space has been deallocated by a call to free or realloc, the behavior is undefined.

这篇关于是否在释放不确定的行为未初始化的指针的结果？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！