Ç - realloc（）的成功在Windows 7，但在Windows XP中失败了，为什么？ [英] c - realloc() succeeds in Windows 7 but fails in Windows XP, why?

问题描述

所以我的这个code有以下的realloc 块：

 的char ** PTR = NULL;无效realloc_ptr（无符号整数new_size）
{
    void *的温度= NULL;    TEMP =的realloc（PTR，new_size * sizeof的（* PTR））;    如果（温度！= NULL）{
        PTR =温度;
    }
    其他{
        出口（EXIT_FAILURE）;
    }
}
 

new_size 递增这个函数被调用权利之前。该数组永远只有扩大。此外， new_size 不超过3在我的code（现在）。

现在上面的的realloc 叫我在测试过程中在Windows 7中工作得很好。当我测试在XP这个code，上述code会成功3次，那就扔在第四次异常。当我回到code（这台计算机不具备code）我会后的确切异常。

我猜我的记忆过于分散，系统无法分配内存的连续块。我测试了我的code内存泄漏和固定所有的人（我希望）。任何想法，为什么发生这种情况？

编辑：

这上面的问题就走了，当我用Doug Lea的 malloc.c 。但我还是想知道为什么会这样。

谢谢！

解决方案

  

当我在XP中测试了这个code，上述code会成功3次，然后将它扔在第四次异常。我会发布的确切异常，当我回到了code（这台计算机不具备code）。

这（例外）意味着你要么无效指针（或指数）的地方（也许，未初始化）和/或内存损坏。 的realloc（）必须默默失败并返回NULL，如果要求不能得到满足。

和它是完全正常的有不同的操作系统不同的行为。

So this code of mine had the following realloc block:

char **ptr = NULL;

void realloc_ptr(unsigned int new_size)
{    
    void *temp = NULL;

    temp = realloc(ptr, new_size * sizeof(*ptr));

    if(temp != NULL) {
        ptr = temp;
    }
    else {
        exit(EXIT_FAILURE);
    }
}

new_size is incremented right before this function is called. This array is always only expanded. Also, new_size never exceeds 3 in my code (for now).

Now the above realloc call worked fine during my testing in Windows 7. When I tested this code in XP, the above code would succeed 3 times and then it would throw an exception on the 4th time. I'll post the exact exception when I get back to the code (this computer doesn't have the code).

I'm guessing that my memory is too fragmented and the system could not allocate a contiguous block of memory. I have tested my code for memory leaks and fixed all of them (I hope). Any ideas why this is happening?

EDIT:

This above problem went away when I used Doug Lea's malloc.c. But I still want to know why this happened.

Thanks!

解决方案

When I tested this code in XP, the above code would succeed 3 times and then it would throw an exception on the 4th time. I'll post the exact exception when I get back to the code (this computer doesn't have the code).

That (the exception) means you either have invalid pointers (or indices) somewhere (perhaps, uninitialized) and/or a memory corruption. realloc() must fail silently and return NULL if the request cannot be satisfied.

And it's perfectly normal to have different behavior on different OSes.

这篇关于Ç - realloc（）的成功在Windows 7，但在Windows XP中失败了，为什么？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！