c++ - CRT 不打印内存泄漏的行号

Question

我有下面的代码，我认为它基于 Finding Memory Leaks Using the CRT Library , 应该打印出内存泄漏的行号。

#include "stdafx.h"
#define _CRTDBG_MAP_ALLOC
#include <stdlib.h>
#include <crtdbg.h>
#include <iostream>


void derp()
{
    int* q = new int;

}

int main()
{
    _CrtSetDbgFlag(_CRTDBG_ALLOC_MEM_DF | _CRTDBG_LEAK_CHECK_DF);
    derp();
    return 0;
}

当我运行它时，我得到以下信息:

Detected memory leaks!
Dumping objects ->
{75} normal block at 0x0067E930, 4 bytes long.
 Data: <    > CD CD CD CD 
Object dump complete.

根据 Microsoft 的文档，我希望看到分配泄漏内存的行的打印输出，但我没有看到。

我做错了什么？我正在使用 VS2015。

Answer 1

来自MSDN topic :

These techniques work for memory allocated using the standard CRT malloc function. If your program allocates memory using the C++ new operator, however, you may only see the file and line number where the implementation of global operator new calls _malloc_dbg in the memory-leak report. Because that behavior is not very useful, you can change it to report the line that made the allocation by using a macro that looks like this:

#ifdef _DEBUG
    #define DBG_NEW new ( _NORMAL_BLOCK , __FILE__ , __LINE__ )
    // Replace _NORMAL_BLOCK with _CLIENT_BLOCK if you want the
    // allocations to be of _CLIENT_BLOCK type
#else
    #define DBG_NEW new
#endif

然后将您代码中的new替换为DBG_NEW。我测试了它，它可以与您的代码一起正常工作。

---

实际上，用 DBG_NEW 替换代码中的所有地方的 new 是一项非常乏味的任务，所以您可以使用这个宏:

#ifdef _DEBUG
     #define new new( _NORMAL_BLOCK , __FILE__ , __LINE__ )
#else
     #define new new
#endif

我测试了这个方法，它也有效。