开机后显示公共语言运行库调试服务异常

1:修改注册表,在windows环境下打开开始菜单,运行regedit命令,在注册表的编辑窗口中找到win32nt

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5.1.2600.0--hptlbxfx项,将其注册真值改为0即可,关掉窗口.2:有可能你的机子中了伪系统木马病毒,可用卡巴斯基或瑞星2006全盘杀毒一次.若还是不能解决那就只得用第三种方法了:重新装 *** 作系统

使用 Valgrind Memcheck

memcheck工具的使用方式如下:

valgrind --tool=memcheck ./a.out

从上面的命令可以清楚的看到, 主要的命令是valgrind，而我们想使用的工具是通过'-tool'选项来指定的. 上面的‘a.out’指的是我们想使用memcheck运行的可执行文件.

该工具可以检测下列与内存相关的问题 :

未释放内存的使用

对释放后内存的读/写

对已分配内存块尾部的读/写

内存泄露

不匹配的使用malloc/new/new[] 和 free/delete/delete[]

重复释放内存

注意: 上面列出的并不很全面，但却包含了能被该工具检测到的很多普遍的问题.

让我们一个一个地对上面的场景进行讨论:

注意: 下面讨论的所有测试代码都应该使用gcc并且加上-g选项(用来在memcheck的输出中生成行号)进行编译. 就想我们之前讨论过的 C程序被编译成可执行文件, 它需要经历四个不同的阶段.

ToB蓝波湾

翻译于 1 年 前

0人顶

顶 翻译的不错哦!

1. 使用未初始化的内存

Code :

#include <stdio.h>

#include <stdlib.h>

int main(void)

{

char *p

char c = *p

printf("\n [%c]\n",c)

return 0

}

在上面的代码中，我们尝试使用未初始化的指针 ‘p’.

让我们运行Memcheck来看下结果.

$ valgrind --tool=memcheck ./val

==2862== Memcheck, a memory error detector

==2862== Copyright (C) 2002-2009, and GNU GPL'd, by Julian Seward et al.

==2862== Using Valgrind-3.6.0.SVN-Debian and LibVEXrerun with -h for copyright info

==2862== Command: ./val

==2862==

==2862== Use of uninitialised value of size 8

==2862==at 0x400530: main (valgrind.c:8)

==2862==

[#]

==2862==

==2862== HEAP SUMMARY:

==2862== in use at exit: 0 bytes in 0 blocks

==2862== total heap usage: 0 allocs, 0 frees, 0 bytes allocated

==2862==

==2862== All heap blocks were freed -- no leaks are possible

==2862==

==2862== For counts of detected and suppressed errors, rerun with: -v

==2862== Use --track-origins=yes to see where uninitialized values come from

==2862== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 4 from 4)

从上面的输出可以看到,Valgrind检测到了未初始化的变量，然后给出了警告(上面加粗的几行(译者注：貌似上面没有加粗的)).

2. 在内存被释放后进行读/写

Code :

#include <stdio.h>

#include <stdlib.h>

int main(void)

{

char *p = malloc(1)

*p = 'a'

char c = *p

printf("\n [%c]\n",c)

free(p)

c = *p

return 0

}

上面的代码中，我们有一个释放了内存的指针 ‘p’ 然后我们又尝试利用指针获取值.

让我们运行memcheck来看一下Valgrind对这种情况是如何反应的.

$ valgrind --tool=memcheck ./val

==2849== Memcheck, a memory error detector

==2849== Copyright (C) 2002-2009, and GNU GPL'd, by Julian Seward et al.

==2849== Using Valgrind-3.6.0.SVN-Debian and LibVEXrerun with -h for copyright info

==2849== Command: ./val

==2849==

[a]

==2849== Invalid read of size 1

==2849==at 0x400603: main (valgrind.c:30)

==2849== Address 0x51b0040 is 0 bytes inside a block of size 1 free'd

==2849==at 0x4C270BD: free (vg_replace_malloc.c:366)

==2849==by 0x4005FE: main (valgrind.c:29)

==2849==

==2849==

==2849== HEAP SUMMARY:

==2849== in use at exit: 0 bytes in 0 blocks

==2849== total heap usage: 1 allocs, 1 frees, 1 bytes allocated

==2849==

==2849== All heap blocks were freed -- no leaks are possible

==2849==

==2849== For counts of detected and suppressed errors, rerun with: -v

==2849== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 4 from 4)

从上面的输出内容可以看到，Valgrind检测到了无效的读取 *** 作然后输出了警告 ‘Invalid read of size 1′.

另注,使用gdb来调试c程序.

3. 从已分配内存块的尾部进行读/写

Code :

#include <stdio.h>

#include <stdlib.h>

int main(void)

{

char *p = malloc(1)

*p = 'a'

char c = *(p+1)

printf("\n [%c]\n",c)

free(p)

return 0

}

在上面的代码中，我们已经为‘p’分配了一个字节的内存,但我们在将值读取到 ‘c’中的时候使用的是地址p+1.

现在我们使用Valgrind运行上面的代码 :

$ valgrind --tool=memcheck ./val

==2835== Memcheck, a memory error detector

==2835== Copyright (C) 2002-2009, and GNU GPL'd, by Julian Seward et al.

==2835== Using Valgrind-3.6.0.SVN-Debian and LibVEXrerun with -h for copyright info

==2835== Command: ./val

==2835==

==2835== Invalid read of size 1

==2835==at 0x4005D9: main (valgrind.c:25)

==2835== Address 0x51b0041 is 0 bytes after a block of size 1 alloc'd

==2835==at 0x4C274A8: malloc (vg_replace_malloc.c:236)

==2835==by 0x4005C5: main (valgrind.c:22)

==2835==

[]

==2835==

==2835== HEAP SUMMARY:

==2835== in use at exit: 0 bytes in 0 blocks

==2835== total heap usage: 1 allocs, 1 frees, 1 bytes allocated

==2835==

==2835== All heap blocks were freed -- no leaks are possible

==2835==

==2835== For counts of detected and suppressed errors, rerun with: -v

==2835== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 4 from 4)

同样，该工具在这种情况下也检测到了无效的读取 *** 作.

4. 内存泄露

Code:

#include <stdio.h>

#include <stdlib.h>

int main(void)

{

char *p = malloc(1)

*p = 'a'

char c = *p

printf("\n [%c]\n",c)

return 0

}

在这次的代码中, 我们申请了一个字节但是没有将它释放.现在让我们运行Valgrind看看会发生什么：

$ valgrind --tool=memcheck --leak-check=full ./val

==2888== Memcheck, a memory error detector

==2888== Copyright (C) 2002-2009, and GNU GPL'd, by Julian Seward et al.

==2888== Using Valgrind-3.6.0.SVN-Debian and LibVEXrerun with -h for copyright info

==2888== Command: ./val

==2888==

[a]

==2888==

==2888== HEAP SUMMARY:

==2888== in use at exit: 1 bytes in 1 blocks

==2888== total heap usage: 1 allocs, 0 frees, 1 bytes allocated

==2888==

==2888== 1 bytes in 1 blocks are definitely lost in loss record 1 of 1

==2888==at 0x4C274A8: malloc (vg_replace_malloc.c:236)

==2888==by 0x400575: main (valgrind.c:6)

==2888==

==2888== LEAK SUMMARY:

==2888==definitely lost: 1 bytes in 1 blocks

==2888==indirectly lost: 0 bytes in 0 blocks

==2888== possibly lost: 0 bytes in 0 blocks

==2888==still reachable: 0 bytes in 0 blocks

==2888== suppressed: 0 bytes in 0 blocks

==2888==

==2888== For counts of detected and suppressed errors, rerun with: -v

==2888== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 4 from 4)

输出行(上面加粗的部分)显示，该工具能够检测到内存的泄露.

Valgrind的使用非常简单，valgrind命令的格式如下：

valgrind [valgrind-options]your-prog [your-prog options]

一些常用的选项如下：

-h --help

显示帮助信息。

--version

显示valgrind内核的版本，每个工具都有各自的版本。

-q --quiet

安静地运行，只打印错误信息。

-v --verbose

打印更详细的信息。

--tool= [default: memcheck]

最常用的选项。运行valgrind中名为toolname的工具。如果省略工具名，默认运行memcheck。

--db-attach= [default: no]

绑定到调试器上，便于调试错误。

我们通过例子看一下它的具体使用。我们构造一个存在内存泄漏的C程序，如下：

#include <stdio.h>

#include <stdlib.h>

int*Test(void)

{

int* x = malloc(10 * sizeof(int))

delete x// problem 1: heap block overrun, problem 2: memory leak --x not free, only first address

return x

}

int main(void)

{

int count

Test()

printf("i =%d/n", count)//problem 3: use uninitialised value.

return 0

}

$ gcc -Wall -o Test Test.c

$ valgrind --tool=memcheck ./ Test

$valgrind --tool=memcheck --leak-check=yes ./Test

三、安装

sudo apt-get install valgrind

Linux下Valgrind的使用概述

Linux下利用Valgrind工具进行内存泄露检测和性能分析

Ubuntu 内存泄漏检测工具Valgrind的安装

Valgrind--Linux下的内存调试和代码解剖工具

应用 Valgrind 发现 Linux 程序的内存问题

更多关于Linux基础学习的问题，请查阅书籍《Linux就该这么学》

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