[心得] memory leak test tool: valgrind

[dozer (rezod)]

我照著q大提供的連結試用了valgrind
因為我用的是Ubuntu
所以是直接上repository下載的版本 (valgrind-3.2.0-Debian)
用法跟gdb差不多 很直覺
查memeory leak最簡單的方法就是用

% valgrind --tool=memcheck program_name

如果一切正常沒有漏記憶體 會有如下的畫面：
==22574== Memcheck, a memory error detector.
==22574== Copyright (C) 2002-2006, and GNU GPL'd, by Julian Seward et al.
==22574== Using LibVEX rev 1606, a library for dynamic binary translation.
==22574== Copyright (C) 2004-2006, and GNU GPL'd, by OpenWorks LLP.
==22574== Using valgrind-3.2.0-Debian, a dynamic binary instrumentation
framework.
==22574== Copyright (C) 2000-2006, and GNU GPL'd, by Julian Seward et al.
==22574== For more details, rerun with: -v
==22574==
==22574==
==22574== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 31 from 1)
==22574== malloc/free: in use at exit: 0 bytes in 0 blocks.
==22574== malloc/free: 10,319 allocs, 10,319 frees, 156,300 bytes allocated.
==22574== For counts of detected errors, rerun with: -v
==22574== All heap blocks were freed -- no leaks are possible.

除了檢查漏記憶體之外 他也會找一些看起來不太對勁的語法
比如我之前有一個用來去除字串前後空白的函式
裏面用到這樣的語法

if(i) strcpy(string,string+i);

(這種東西碰到string是字串常數就會segfault 只是之前偷懶不去管)
他就警告我source跟destination都一樣之類的
嚴格的程度比gcc -Wall更高

另外像C的automatic variable如果宣告太大的陣列
(像char buffer[1024*1024] 之類的東西)
有些位址好像會overlap 運氣不好可能就會當的亂七八糟
gcc不會管 但他也會告訴你

總之 目前用的挺滿意 供大家參考囉！




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◆ From: 140.109.176.158
※ 編輯: dozer           來自: 140.109.176.158      (12/15 18:03)
→ qrtt1:呵..建議標題-> memory leak test tool: valgrind
→ qrtt1:比較方便爬文的人search
※ 編輯: dozer           來自: 140.109.176.158      (12/15 21:29)
→ dozer:完成啦^+++^
※ 編輯: dozer           來自: 122.126.35.54        (12/15 23:52)
→ qrtt1:呵，恭禧啊。分享是件快樂的事啊^^
→ dozer:補充一點 編譯binary時要記得加-g才能用valgrind來debug