在visual studio中，有一个内置的内存泄漏检测器，称为C运行时库。当主函数返回后程序退出时，CRT将检查应用程序的调试堆。如果在调试堆上仍然分配了任何块，那么就存在内存泄漏。 本论坛讨论了在C/ c++中避免内存泄漏的一些方法。

在应用程序代码中不应该使用“new”或“delete”。相反，应该创建一个使用管理器/工作人员习惯用法的新类型，其中管理器类分配和释放内存，并将所有其他操作转发给工作人员对象。

不幸的是，这比它应该做的要多，因为c++没有“operator .”的重载。如果存在多态，则工作量更大。

但是这样做是值得的，因为这样您就不必担心内存泄漏，这意味着您甚至不需要寻找它们。

MTuner是一个免费的多平台内存分析、泄漏检测和分析工具，支持MSVC、GCC和Clang编译器。功能包括:

基于时间轴的内存使用历史和活动内存块 强大的内存操作过滤基于堆，内存标签，时间范围等。 SDK手动仪表与完整的源代码 通过命令行使用支持持续集成 调用堆栈树和树映射导航 更多。

用户可以通过GCC或Clang cross配置任何软件定位平台 编译器。MTuner内置对Windows、PlayStation 4和PlayStation 3平台的支持。

Visual Leak Detector (VLD)是一个免费的、健壮的、开源的Visual c++内存泄漏检测系统。

当您在Visual Studio调试器下运行程序时，Visual Leak Detector将在调试会话结束时输出内存泄漏报告。泄漏报告包括完整的调用堆栈，显示泄漏的内存块是如何分配的。双击调用堆栈中的一行，以跳转到编辑器窗口中的该文件和该行。

如果你只有崩溃转储，你可以使用Windbg !heap -l命令，它将检测泄漏的堆块。最好打开gflags选项:“创建用户模式堆栈跟踪数据库”，然后您将看到内存分配调用堆栈。

自动内存泄漏检查器的概述

在这个回答中，我在一个简单易懂的内存泄漏示例中比较了几种不同的内存泄漏检查程序。

在做任何事情之前，请参阅ASan wiki中比较人类已知所有工具的巨大表格:https://github.com/google/sanitizers/wiki/AddressSanitizerComparisonOfMemoryTools/d06210f759fec97066888e5f27c7e722832b0924

分析的例子如下:

c

#include <stdlib.h>

void * my_malloc(size_t n) {
    return malloc(n);
}

void leaky(size_t n, int do_leak) {
    void *p = my_malloc(n);
    if (!do_leak) {
        free(p);
    }
}

int main(void) {
    leaky(0x10, 0);
    leaky(0x10, 1);
    leaky(0x100, 0);
    leaky(0x100, 1);
    leaky(0x1000, 0);
    leaky(0x1000, 1);
}

GitHub上游。

我们将尝试看看不同的工具如何清楚地向我们指出泄漏的调用。

从gperftools通过谷歌

https://github.com/gperftools/gperftools

Ubuntu 19.04的用法:

sudo apt-get install google-perftools
gcc -ggdb3 -o main.out main.c -ltcmalloc
PPROF_PATH=/usr/bin/google-pprof \
  HEAPCHECK=normal \
  HEAPPROFILE=ble \
  ./main.out \
;
google-pprof main.out ble.0001.heap --text

程序运行的输出包含内存泄漏分析:

WARNING: Perftools heap leak checker is active -- Performance may suffer
Starting tracking the heap
Dumping heap profile to ble.0001.heap (Exiting, 4 kB in use)
Have memory regions w/o callers: might report false leaks
Leak check _main_ detected leaks of 272 bytes in 2 objects
The 2 largest leaks:
Using local file ./main.out.
Leak of 256 bytes in 1 objects allocated from:
        @ 555bf6e5815d my_malloc
        @ 555bf6e5817a leaky
        @ 555bf6e581d3 main
        @ 7f71e88c9b6b __libc_start_main
        @ 555bf6e5808a _start
Leak of 16 bytes in 1 objects allocated from:
        @ 555bf6e5815d my_malloc
        @ 555bf6e5817a leaky
        @ 555bf6e581b5 main
        @ 7f71e88c9b6b __libc_start_main
        @ 555bf6e5808a _start


If the preceding stack traces are not enough to find the leaks, try running THIS shell command:

pprof ./main.out "/tmp/main.out.24744._main_-end.heap" --inuse_objects --lines --heapcheck  --edgefraction=1e-10 --nodefraction=1e-10 --gv

If you are still puzzled about why the leaks are there, try rerunning this program with HEAP_CHECK_TEST_POINTER_ALIGNMENT=1 and/or with HEAP_CHECK_MAX_POINTER_OFFSET=-1
If the leak report occurs in a small fraction of runs, try running with TCMALLOC_MAX_FREE_QUEUE_SIZE of few hundred MB or with TCMALLOC_RECLAIM_MEMORY=false, it might help find leaks more re
Exiting with error code (instead of crashing) because of whole-program memory leaks

google-pprof的输出包含堆使用分析:

Using local file main.out.
Using local file ble.0001.heap.
Total: 0.0 MB
     0.0 100.0% 100.0%      0.0 100.0% my_malloc
     0.0   0.0% 100.0%      0.0 100.0% __libc_start_main
     0.0   0.0% 100.0%      0.0 100.0% _start
     0.0   0.0% 100.0%      0.0 100.0% leaky
     0.0   0.0% 100.0%      0.0 100.0% main

输出为我们指出了三个泄漏中的两个:

Leak of 256 bytes in 1 objects allocated from:
        @ 555bf6e5815d my_malloc
        @ 555bf6e5817a leaky
        @ 555bf6e581d3 main
        @ 7f71e88c9b6b __libc_start_main
        @ 555bf6e5808a _start
Leak of 16 bytes in 1 objects allocated from:
        @ 555bf6e5815d my_malloc
        @ 555bf6e5817a leaky
        @ 555bf6e581b5 main
        @ 7f71e88c9b6b __libc_start_main
        @ 555bf6e5808a _start

我不知道为什么第三个没出现

在任何情况下，通常当某些东西泄漏时，它会发生很多次，当我在一个真实的项目中使用它时，我只是很容易就被指出泄漏函数。

正如输出本身所提到的，这会导致显著的执行速度放缓。

进一步文件载于:

https://gperftools.github.io/gperftools/heap_checker.html https://gperftools.github.io/gperftools/heapprofile.html

参见:如何使用TCMalloc?

在Ubuntu 19.04中测试，google-perftools 2.5-2。

地址消毒(ASan)也由谷歌

https://github.com/google/sanitizers

前面提到过:如何在c++代码/项目中找到内存泄漏?TODO vs tcmalloc。

这已经集成到GCC中，所以你可以这样做:

gcc -fsanitize=address -ggdb3 -o main.out main.c
./main.out 

和执行输出:

=================================================================
==27223==ERROR: LeakSanitizer: detected memory leaks

Direct leak of 4096 byte(s) in 1 object(s) allocated from:
    #0 0x7fabbefc5448 in malloc (/usr/lib/x86_64-linux-gnu/libasan.so.5+0x10c448)
    #1 0x55bf86c5f17c in my_malloc /home/ciro/test/main.c:4
    #2 0x55bf86c5f199 in leaky /home/ciro/test/main.c:8
    #3 0x55bf86c5f210 in main /home/ciro/test/main.c:20
    #4 0x7fabbecf4b6a in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x26b6a)

Direct leak of 256 byte(s) in 1 object(s) allocated from:
    #0 0x7fabbefc5448 in malloc (/usr/lib/x86_64-linux-gnu/libasan.so.5+0x10c448)
    #1 0x55bf86c5f17c in my_malloc /home/ciro/test/main.c:4
    #2 0x55bf86c5f199 in leaky /home/ciro/test/main.c:8
    #3 0x55bf86c5f1f2 in main /home/ciro/test/main.c:18
    #4 0x7fabbecf4b6a in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x26b6a)

Direct leak of 16 byte(s) in 1 object(s) allocated from:
    #0 0x7fabbefc5448 in malloc (/usr/lib/x86_64-linux-gnu/libasan.so.5+0x10c448)
    #1 0x55bf86c5f17c in my_malloc /home/ciro/test/main.c:4
    #2 0x55bf86c5f199 in leaky /home/ciro/test/main.c:8
    #3 0x55bf86c5f1d4 in main /home/ciro/test/main.c:16
    #4 0x7fabbecf4b6a in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x26b6a)

SUMMARY: AddressSanitizer: 4368 byte(s) leaked in 3 allocation(s).

它清楚地识别所有泄漏。好了!

ASan还可以做其他很酷的检查，比如越界写入:检测到堆栈破坏

在Ubuntu 19.04, GCC 8.3.0中测试。

Valgrind

http://www.valgrind.org/

之前提到过:https://stackoverflow.com/a/37661630/895245

用法:

sudo apt-get install valgrind
gcc -ggdb3 -o main.out main.c
valgrind --leak-check=yes ./main.out

输出:

==32178== Memcheck, a memory error detector
==32178== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==32178== Using Valgrind-3.14.0 and LibVEX; rerun with -h for copyright info
==32178== Command: ./main.out
==32178== 
==32178== 
==32178== HEAP SUMMARY:
==32178==     in use at exit: 4,368 bytes in 3 blocks
==32178==   total heap usage: 6 allocs, 3 frees, 8,736 bytes allocated
==32178== 
==32178== 16 bytes in 1 blocks are definitely lost in loss record 1 of 3
==32178==    at 0x483874F: malloc (in /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so)
==32178==    by 0x10915C: my_malloc (main.c:4)
==32178==    by 0x109179: leaky (main.c:8)
==32178==    by 0x1091B4: main (main.c:16)
==32178== 
==32178== 256 bytes in 1 blocks are definitely lost in loss record 2 of 3
==32178==    at 0x483874F: malloc (in /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so)
==32178==    by 0x10915C: my_malloc (main.c:4)
==32178==    by 0x109179: leaky (main.c:8)
==32178==    by 0x1091D2: main (main.c:18)
==32178== 
==32178== 4,096 bytes in 1 blocks are definitely lost in loss record 3 of 3
==32178==    at 0x483874F: malloc (in /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so)
==32178==    by 0x10915C: my_malloc (main.c:4)
==32178==    by 0x109179: leaky (main.c:8)
==32178==    by 0x1091F0: main (main.c:20)
==32178== 
==32178== LEAK SUMMARY:
==32178==    definitely lost: 4,368 bytes in 3 blocks
==32178==    indirectly lost: 0 bytes in 0 blocks
==32178==      possibly lost: 0 bytes in 0 blocks
==32178==    still reachable: 0 bytes in 0 blocks
==32178==         suppressed: 0 bytes in 0 blocks
==32178== 
==32178== For counts of detected and suppressed errors, rerun with: -v
==32178== ERROR SUMMARY: 3 errors from 3 contexts (suppressed: 0 from 0)

所以再一次，所有的泄漏都被检测到了。

请参见:如何使用valgrind查找内存泄漏?

在Ubuntu 19.04, valgrind 3.14.0中测试。

Search your code for occurrences of new, and make sure that they all occur within a constructor with a matching delete in a destructor. Make sure that this is the only possibly throwing operation in that constructor. A simple way to do this is to wrap all pointers in std::auto_ptr, or boost::scoped_ptr (depending on whether or not you need move semantics). For all future code just ensure that every resource is owned by an object that cleans up the resource in its destructor. If you need move semantics then you can upgrade to a compiler that supports r-value references (VS2010 does I believe) and create move constructors. If you don't want to do that then you can use a variety of tricky techniques involving conscientious usage of swap, or try the Boost.Move library.