整个测试代码包含在main.cpp中,如下:
#include <iostream>
using std::cout;
using std::endl;
void f(int i) {
int* pi = new int;
*pi = i;
std::cout << "*pi = " << *pi << std::endl;
}
int main(int argc, char *argv[]) {
int i = 0;
while (i < 10000) {
f(i);
++i;
}
return 0;
}
我编译时没有优化-O0
(来自 Eclipse Qt 项目):
g++ -c -pipe -O0 -Wall -W -D_REENTRANT -DQT_NO_DEBUG -DQT_GUI_LIB -DQT_CORE_LIB -DQT_SHARED -I/usr/share/qt4/mkspecs/linux-g++ -I. -I/usr/include/qt4/QtCore -I/usr/include/qt4/QtGui -I/usr/include/qt4 -Irelease -o release/main.o main.cpp
然后链接如下:
g++ -Wl,-O0 -o test release/main.o -L/usr/lib -lQtGui -lQtCore -lpthread
我通过 valgrind 运行可执行文件并得到以下输出:
laptop:~/workspace/test$ valgrind --leak-check=yes test
==3939== Memcheck, a memory error detector
==3939== Copyright (C) 2002-2009, and GNU GPL'd, by Julian Seward et al.
==3939== Using Valgrind-3.6.0.SVN-Debian and LibVEX; rerun with -h for copyright info
==3939== Command: test
==3939==
==3939==
==3939== HEAP SUMMARY:
==3939== in use at exit: 0 bytes in 0 blocks
==3939== total heap usage: 1,387 allocs, 1,387 frees, 64,394 bytes allocated
==3939==
==3939== All heap blocks were freed -- no leaks are possible
==3939==
==3939== For counts of detected and suppressed errors, rerun with: -v
==3939== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 13 from 8)
我相信 valgrind 应该报告内存泄漏,而不是因为调用中分配的堆内存而不可能发生泄漏new int
编辑:更改上面的代码以使用 std::cout 而不是 qDebug() 具有相同的结果
如果我编译并链接没有 Qt 依赖项的相同代码(来自 Eclipse CDT 项目),valgrind 会检测到泄漏:
g++ -O0 -g3 -Wall -c -fmessage-length=0 -MMD -MP -MF"main.d" -MT"main.d" -o"main.o" "../main.cpp"
g++ -o"test2" ./main.o
==4604== HEAP SUMMARY:
==4604== in use at exit: 40,000 bytes in 10,000 blocks
==4604== total heap usage: 10,000 allocs, 0 frees, 40,000 bytes allocated
==4604==
==4604== 40,000 bytes in 10,000 blocks are definitely lost in loss record 1 of 1
==4604== at 0x402569A: operator new(unsigned int) (vg_replace_malloc.c:255)
==4604== by 0x8048756: f(int) (main.cpp:7)
==4604== by 0x80487BB: main (main.cpp:18)
==4604==
==4604== LEAK SUMMARY:
==4604== definitely lost: 40,000 bytes in 10,000 blocks
==4604== indirectly lost: 0 bytes in 0 blocks
==4604== possibly lost: 0 bytes in 0 blocks
==4604== still reachable: 0 bytes in 0 blocks
==4604== suppressed: 0 bytes in 0 blocks
==4604==
==4604== For counts of detected and suppressed errors, rerun with: -v
==4604== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 19 from 8)
我正在使用 Kubuntu 10.04 32 位,并尝试了调试和发布版本,我做错了什么或者为什么 valgrind 在与 Qt 链接时不报告内存泄漏?