[英]VC++ debug assertion failed on program exit
I'm trying to create a linked list class template (Yes, I know there's one in the c++ library but I wanted to create my own for fun). 我正在尝试创建一个链接列表类模板(是的,我知道c ++库中有一个模板,但是我想自己创建一个有趣的模板)。 I've traced through the code and all seems well until the program exits. 我已经遍历了代码,直到程序退出,一切似乎都很好。
Here's the used code: 这是使用的代码:
list.h: list.h:
#ifndef LIST_H
#define LIST_H
#include "misc.h"
template <typename T> class CList {
private:
class CNode {
friend CList;
private: T data;
CNode* next;
public: CNode() : next(NULL) {}
~CNode() { delete [] next; }
};
private: int length;
CNode* first;
public:
CList() : length(0), first(NULL) {}
CList(int i_length) : first(NULL) {
int i;
CNode* cur = NULL;
CNode* prev = NULL;
if (i_length < 0) length = 0;
else length = i_length;
for (i=0;i<length;i++) {
// allocate new CNode on heap
cur = new2<CNode>();
// attach preceding CNode pointer
if (prev) prev->next = cur;
else first = cur;
prev = cur;
}
}
~CList() { delete first; }
};
misc.h 杂项
#ifndef MISC_H
#define MISC_H
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
inline void terminate( const char* message, int code ) {
printf("\n\n%s\n\n",message);
system("pause");
exit(code);
};
template <typename T> inline T* new2() {
T* ret = new T;
if (!ret) terminate("Insufficient Memory",-2);
return ret;
}
template <typename T> inline T* new2(int num) {
if (num <= 0) terminate("Invalid Argument",-1);
T* ret = new T[num];
if(!ret) terminate("Insufficient Memory",-2);
return ret;
}
#endif
main.cpp main.cpp
#include <stdio.h>
#include <stdlib.h>
#include "../Misc/misc.h"
#include "../Misc/list.h"
int main(int argc, char* argv[]) {
//CList<int> m;
CList<int> n(5);
system("pause");
return 0;
}
Here is what the variable "n" looks like at the breakpoint just before "return 0;". 这是变量“ n”在“返回0;”之前的断点处的外观。
http://s20.beta.photobucket.com/user/marshallbs/media/Untitled_zps52497d5d.png.html http://s20.beta.photobucket.com/user/marshallbs/media/Untitled_zps52497d5d.png.html
Here's the context in which the error occurs. 这是发生错误的上下文。 Unfortunately at this point I can no longer view the variable "n" on the watch list. 不幸的是,此时我无法再在监视列表中查看变量“ n”。
_mlock(_HEAP_LOCK); /* block other threads */
__TRY
/* get a pointer to memory block header */
pHead = pHdr(pUserData);
/* verify block type */
_ASSERTE(_BLOCK_TYPE_IS_VALID(pHead->nBlockUse));
There is no error when I use the default constructor for my list. 当我为列表使用默认构造函数时没有错误。 I don't understand what's going on as the memory release process should stop when it reaches the fifth CNode object which has a null "next" pointer. 我不知道发生了什么,因为当内存释放过程到达具有空“ next”指针的第五个CNode对象时,它应该停止。 It acts as though it's trying to releasing an invalid non-null pointer but I don't see how this can happen. 它的行为就像是试图释放无效的非null指针,但我不知道这怎么发生。
One problem is that you allocate next
using new
and free it using delete[]
. 一个问题是,您使用new
分配next
,然后使用delete[]
释放它。 This is undefined behaviour. 这是未定义的行为。
Allocation: 分配:
cur = new2<CNode>(); // new2 uses `new' and not `new[]'
Deallocation: 解除分配:
~CNode() { delete [] next; }
Replace the latter with delete next;
delete next;
用delete next;
替换后者delete next;
. 。
I built and ran (from the debugger) the code as-is and got no assertion failures. 我按原样构建并运行(从调试器运行)代码,没有断言失败。 In fact, there is no memory deallocation at all because CList doesn't have a destructor (didn't you post the complete code?). 实际上,根本没有内存释放,因为CList没有析构函数(您不发布完整的代码吗?)。
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