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我编写了一个测试 C++ 程序来检查 valgrind 的输出。代码是

#include <iostream>

void f() {
    int *pp = new int(1);
    std::cout << "pp is " << *pp << "\n";
}

int main() {
    f();
    return 0;
}

我使用的 valgrind 命令是

valgrind --leak-check=yes ./a.out

Valgrind 的输出是

==2255== HEAP SUMMARY:
==2255==     in use at exit: 4 bytes in 1 blocks
==2255==   total heap usage: 1 allocs, 0 frees, 4 bytes allocated
==2255== 
==2255== 4 bytes in 1 blocks are definitely lost in loss record 1 of 1
==2255==    at 0x4C2B1C7: operator new(unsigned long) (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==2255==    by 0x400786: f() (in /run/shm/a.out)
==2255==    by 0x4007CC: main (in /run/shm/a.out)
==2255== 
==2255== LEAK SUMMARY:
==2255==    definitely lost: 4 bytes in 1 blocks
==2255==    indirectly lost: 0 bytes in 0 blocks
==2255==      possibly lost: 0 bytes in 0 blocks
==2255==    still reachable: 0 bytes in 0 blocks
==2255==         suppressed: 0 bytes in 0 blocks

我正在使用 Ubuntu 机器：Linux Sun 3.2.0-27-generic #43-Ubuntu SMP Fri Jul 6 14:25:57 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux

gcc 版本“4.6.3”

我使用的 gcc 参数“-g -m64”

我认为它应该是八个字节，对吧？

4

2 回答 2

2

sizeof(int)==8不，除非在您的平台上，否则它不应该是八个字节。

您正在分配和泄漏单个int，而不是指针。

于 2012-10-21T14:37:46.413 回答
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您不分配指针数组，而是分配大小为 1 的整数数组。因此，您仅在内存中分配整数的大小。唯一的指针是存储新分配数组地址的局部变量。

如果要分配指针，请执行void **arr = new void*[1];

于 2012-10-21T14:40:15.933 回答