dmalloc用法快速入門

dmalloc是一個簡單易用的C/C++內存leak檢查工具，以一個運行庫的方式發布。

dmalloc能夠檢查出直到程序運行結束還沒有釋放的內存，并且能夠精確指出在
哪個源文件的第幾行。

dmalloc 主頁：?http://dmalloc.com

支持的平臺：AIX, BSD/OS, DG/UX, Free/Net/OpenBSD, GNU/Hurd, HPUX, Irix, Linux, MS-DOG, NeXT, OSF, SCO, Solaris, SunOS, Ultrix, Unixware, Windoze, and even Unicos on a Cray T3E

最新版本： 5.5.2

安裝：下載?http://dmalloc.com/releases/dmalloc-5.5.2.tgz

tar?zxvf dmalloc-5.5.2.tgz

cd?dmalloc-5.5.2

./configure

make

make?install

設置環境變量：
對于 Bash, ksh, and zsh (http://www.zsh.org/), 在 `.bashrc', `.profile', or `.zshrc'
文件中加入一行 ( -b 參數表示針對Bash的輸出):

function dmalloc { eval `command dmalloc -b $*`; }

然后重新登陸用戶，或者執行: source ~/.bashrc 或 source ~/.profile

接下面執行:

dmalloc -l logfile -i?100?low

在源文件中添加下面的C代碼：

#ifdef DMALLOC
#include "dmalloc.h"
#endif

編譯使用的CFLAGS: -DDMALLOC -DDMALLOC_FUNC_CHECK

如： gcc -DDMALLOC -DDMALLOC_FUNC_CHECK dm_test.c

執行:
./a.out

運行上面的命令會在當前目錄下生成 logfile文件，查看logfile的內容如下：

cat logfile

1214894489: 2: Dmalloc version '5.5.2' from 'http://dmalloc.com/'

1214894489: 2: flags = 0x4e48503, logfile 'logfile'

1214894489: 2: interval = 100, addr = 0, seen # = 0, limit = 0

1214894489: 2: starting time = 1214894489

1214894489: 2: process pid = 9560

1214894489: 2: Dumping Chunk Statistics:

1214894489: 2: basic-block 4096 bytes, alignment 8 bytes

1214894489: 2: heap address range: 0xb8020000 to 0xb8029000, 36864 bytes

1214894489: 2: ? ? user blocks: 1 blocks, 4043 bytes (10%)

1214894489: 2: ? ?admin blocks: 8 blocks, 32768 bytes (89%)

1214894489: 2: ? ?total blocks: 9 blocks, 36864 bytes

1214894489: 2: heap checked 1

1214894489: 2: alloc calls: malloc 2, calloc 0, realloc 0, free 0

1214894489: 2: alloc calls: recalloc 0, memalign 0, valloc 0

1214894489: 2: alloc calls: new 0, delete 0

1214894489: 2: ? current memory in use: 11 bytes (2 pnts)

1214894489: 2: ?total memory allocated: 11 bytes (2 pnts)

1214894489: 2: ?max in use at one time: 11 bytes (2 pnts)

1214894489: 2: max alloced with 1 call: 6 bytes

1214894489: 2: max unused memory space: 53 bytes (82%)

1214894489: 2: top 10 allocations:

1214894489: 2: ?total-size ?count in-use-size ?count ?source

1214894489: 2: ? ? ? ? ? 6 ? ? ?1 ? ? ? ? ? 6 ? ? ?1 ?dm_test.c:71

1214894489: 2: ? ? ? ? ? 5 ? ? ?1 ? ? ? ? ? 5 ? ? ?1 ?dm_test.c:69

1214894489: 2: ? ? ? ? ?11 ? ? ?2 ? ? ? ? ?11 ? ? ?2 ?Total of 2

1214894489: 2: Dumping Not-Freed Pointers Changed Since Start:

1214894489: 2: ?not freed: '0xb8028fc8|s1' (6 bytes) from 'dm_test.c:71'

1214894489: 2: ?not freed: '0xb8028fe8|s1' (5 bytes) from 'dm_test.c:69'

1214894489: 2: ?total-size ?count ?source

1214894489: 2: ? ? ? ? ? 6 ? ? ?1 ?dm_test.c:71

1214894489: 2: ? ? ? ? ? 5 ? ? ?1 ?dm_test.c:69

1214894489: 2: ? ? ? ? ?11 ? ? ?2 ?Total of 2

1214894489: 2: ending time = 1214894489, elapsed since start = 0:00:00

那么，哪個地方的內存leak就一目了然了。

//====== dm_test.c 源代碼 =============

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#ifdef DMALLOC

#include <dmalloc.h>

#endif

int?main(int?argc,?char?**argv)

{

char?*str;

str?=?malloc(5);

str?=?malloc(6);

return?0;

}

參見文檔：

http://dmalloc.com/docs/latest/dmalloc.pdf.gz

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