Clang ++生成泄漏内存的可执行文件,关于std :: function和lambda

Question

ArchLinux(i686)上的Clang ++ 3.2用于构建以下C++ 11代码

#include <iostream>
#include <functional>

typedef std::function<void ()> Action;
typedef std::function<int ()> Generator;

Action act(Generator const& gen)
{
    return [=]()
    {
        std::cout << gen() << std::endl;
    };
}

int main()
{
    static Generator const gen([]() { return 0; });
    act(gen);
    return 0;
}

随着clang++ test.cpp -std=c++0x && valgrind --leak-check=full --log-file=tmp.log.memcheck ./a.out然后我得到

==600== HEAP SUMMARY:
==600==     in use at exit: 1 bytes in 1 blocks
==600==   total heap usage: 3 allocs, 2 frees, 18 bytes allocated
==600== 
==600== 1 bytes in 1 blocks are definitely lost in loss record 1 of 1
==600==    at 0x402B124: operator new(unsigned int) (in /usr/lib/valgrind/vgpreload_memcheck-x86-linux.so)
==600==    by 0x8048D4F: std::_Function_base::_Base_manager<main::$_1>::_M_clone(std::_Any_data&, std::_Any_data const&, std::integral_constant<bool, false>) (in /home/neuront/a.out)
==600==    by 0x8048C21: std::_Function_base::_Base_manager<main::$_1>::_M_manager(std::_Any_data&, std::_Any_data const&, std::_Manager_operation) (in /home/neuront/a.out)
==600==    by 0x8049455: std::function<int ()>::function(std::function<int ()> const&) (in /home/neuront/a.out)
==600==    by 0x8049283: std::function<int ()>::function(std::function<int ()> const&) (in /home/neuront/a.out)
==600==    by 0x80489B1: act(std::function<int ()> const&) (in /home/neuront/a.out)
==600==    by 0x8048A6C: main (in /home/neuront/a.out)
==600== 
==600== LEAK SUMMARY:
==600==    definitely lost: 1 bytes in 1 blocks
==600==    indirectly lost: 0 bytes in 0 blocks
==600==      possibly lost: 0 bytes in 0 blocks
==600==    still reachable: 0 bytes in 0 blocks
==600==         suppressed: 0 bytes in 0 blocks
==600== 
==600== For counts of detected and suppressed errors, rerun with: -v
==600== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 0 from 0)

我不确定该代码是否有任何问题(并导致只有一个字节的泄漏),但如果使用g ++ 4.7进行编译,则不会有内存泄漏.有什么建议吗？

Answer 1

众所周知，静态变量“导致”了 valgrind 中复杂对象的内存泄漏，这些复杂对象还在堆上分配了一些东西（例如 STL 容器等）。

在实践中，没有什么可担心的，但它当然破坏了“我的程序没有泄漏”这一事实，并使真正的泄漏更难发现。

我假设 g++ 只是设法将生成器完全保留在 BSS 区域中，而 clang 认为需要在堆上分配一个字节。