为什么使用 make_unique<> 将函数传递给线程会导致 Valgrind 中的内存泄漏？

Why does passing a function to a thread using make_unique<> cause a memory leak in Valgrind?

本文关键字：线程 Valgrind 内存 泄漏 make unique lt 为什么 函数 gt      更新时间：2023-10-16

我正在尝试这样做：

int main(){
std::unique_ptr<std::thread> up(nullptr);
up = std::make_unique<std::thread>(upload, url, path);
return 0;
}

其中，upload基本上是一个静态的非成员函数，url和path是std::string的。upload定义为：

static void upload(const string url, const string path){ int sync_status;}

但这总是被报告为瓦尔格林德下的内存泄漏：

249 (80 direct, 169 indirect) bytes in 1 blocks are definitely lost in loss record 151 of 169
==12088==    at 0x4C3017F: operator new(unsigned long) (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==12088==    by 0x1395F9: _S_make_state<std::thread::_Invoker<std::tuple<void (*)(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >), std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> , std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > > > (thread:197)
==12088==    by 0x1395F9: thread<void (&)(std::__cxx11::basic_string<char>, std::__cxx11::basic_string<char>), std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> &> (thread:126)
==12088==    by 0x1395F9: std::_MakeUniq<std::thread>::__single_object std::make_unique<std::thread, void (&)(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> ), std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&>(void (&)(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >), std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> &, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&) (unique_ptr.h:825)
==12088==    by 0x131D8D: main

您的代码最终会调用调用std::terminate的std::thread::~thread，因为线程既没有分离也没有连接。这就是valgrind报告错误的原因。

联接或分离线程。

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