valgrind使用介绍

#下载                 wget http://valgrind.org/downloads/valgrind-3.14.0.tar.bz2   

#解压                 tar xvf valgrind-3.14.0.tar.bz2     

#进入指定目录          cd valgrind-3.14.0/

#指定路径             ./configure --prefix=/home/yuanzhihong/valgrind/valgrind-3.14.0 

make

make install        #若安装不成功，重新make时，记得make clean

#检查是否安装成功
cd bin
./valgrind --version 

 #配置环境变量              vim ~/.bashrc 

#使改变生效               source ~/.bashrc

gcc -Wall main.c -g -o test

==28431== Memcheck, a memory error detector
==28431== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==28431== Using Valgrind-3.14.0 and LibVEX; rerun with -h for copyright info
==28431== Command: ./val

其中==中间的数字（28431）是valgrind的进程ID，也是program的进程ID，它们是同一个进程。

==26787== HEAP SUMMARY:
==26787==     in use at exit: 0 bytes in 0 blocks
==26787==   total heap usage: 2 allocs, 2 frees, 73,728 bytes allocated
==26787== 
==26787== All heap blocks were freed -- no leaks are possible
==26787== 
==26787== For counts of detected and suppressed errors, rerun with: -v
==26787== ERROR SUMMARY: 4 errors from 4 contexts (suppressed: 0 from 0)

//类型1： 使用未初始化的栈空间
#include <iostream>
using namespace std;

int main()
{
    int a;
    cout << a + 3 <<endl;
    return 0;
}

g++ -g -o val 04.cpp
valgrind --log-file=04_1.log --track-origins=yes ./val

Use of uninitialised value of size 8    #计算出未初始化的空间大小,不过计算错了
==26787==    at 0x4F4462E: ??? (in /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.25)
==26787==    by 0x4F44B53: std::ostreambuf_iterator<char, std::char_traits<char> > std::num_put<char, std::ostreambuf_iterator<char, std::char_traits<char> > >::_M_insert_int<long>(std::ostreambuf_iterator<char, std::char_traits<char> >, std::ios_base&, char, long) const (in /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.25)
==26787==    by 0x4F51074: std::ostream& std::ostream::_M_insert<long>(long) (in /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.25)
==26787==    by 0x1088A5: main (04.cpp:15)
==26787==  Uninitialised value was created by a stack allocation   #识别出未初始化的值使用栈空间
==26787==    at 0x10888A: main (04.cpp:13)     #使用栈空间，定位该函数的左括号位置

--track-origins=<yes|no> [default: no]

#include <iostream>
using namespace std;

int main()
{
    int *p = new int;
    return 0;
}

g++ -g -o memleak 05.cpp
valgrind --log-file=05_1.log --leak-check=full ./memleak

==29197== 4 bytes in 1 blocks are definitely lost in loss record 1 of 1
==29197==    at 0x4C3042A: operator new(unsigned long) (vg_replace_malloc.c:334)
==29197==    by 0x10879B: main (05.cpp:13)           #详细错误信息，定位到行号

--leak-check=<no|summary|yes|full>[default: summary]

--show-leak-kinds=<set> [default: definite,possible]

valgrind --log-file=03_8.log --tool=memcheck   ./test

valgrind  ./test  #通用命令