释放指向指针数组的int指针可以很好地工作，但在主程序中崩溃

This code snippet works fine on its own , but once I integrate it to my complete main() function, I get issues with free(0ing, sometimes failing at the first iteration, sometimes failing at a random I and sometimes when I try to free the int pointer pointer.

这个代码片段本身可以正常工作,但是一旦我将它集成到我的完整main()函数中,我就会遇到免费问题(0,有时在第一次迭代时失败,有时会失败,有时我会尝试释放int指针指针。

int main()
{
    int** GPRIListedCoords = calloc(sizeof(int*), GPRIMaxVal);
    int i;
    for(i = 0; i < GPRIMaxVal; i++)
        GPRIListedCoords[i] = calloc(sizeof(int) , 2);
    for( i = 0; i < GPRIMaxVal; i++ )
        free(GPRIListedCoords[i]);
    free(GPRIListedCoords);
    return 0;
}

I create / free the char pointers ( to pointers ) in the same way with no issues.

我以相同的方式创建/释放char指针(指针),没有任何问题。

I tried catching any null pointers, but I'm not getting any.

我尝试捕获任何空指针,但我没有得到任何。

GDB Stack info: http://i.snag.gy/Z3ZqV.jpg

GDB Stack信息:http://i.snag.gy/Z3ZqV.jpg

2 个解决方案

#1

This code sample looks fine. I think the problem is in the other case, where you do something with the allocated pointers. as per the man page of free() (emphasis mine)

此代码示例看起来很好。我认为问题出在另一种情况下,你用分配的指针做一些事情。根据free()的手册页(强调我的)

void free(void *ptr);

void free(void * ptr);

The free() function frees the memory space pointed to by ptr, which must have been returned by a previous call to malloc(), calloc() or realloc(). Otherwise, or if free(ptr) has already been called before, undefined behavior occurs. If ptr is NULL, no operation is performed.

free()函数释放ptr指向的内存空间,该内存空间必须由之前调用malloc(),calloc()或realloc()返回。否则,或者如果之前已经调用了free(ptr),则会发生未定义的行为。如果ptr为NULL,则不执行任何操作。

So, in that case, if the calloc()-ed pointer is changed, you'll face undefined behaviour.

因此,在这种情况下,如果更改了calloc() - ed指针,您将面临未定义的行为。

You can use a debugger (like, gdb on linux) to inspect the allocated memory locations and see if the pointer is changed or not.

您可以使用调试器(例如,linux上的gdb)来检查分配的内存位置,并查看指针是否已更改。

#2

This code looks fine. However, if any part of your code is invoking undefined behaviour, then it could be damaging the internal malloc data structures, which is then causing a crash here.

这段代码看起来不错。但是,如果代码的任何部分正在调用未定义的行为,那么它可能会破坏内部malloc数据结构,从而导致崩溃。

Can you run your program on Linux? I find using valgrind (a Linux tool) can often shake out such bugs.

你可以在Linux上运行你的程序吗?我发现使用valgrind(Linux工具)可以经常摆脱这样的错误。

#1