是否可以安全地混合pthread.h和C ++ 11标准库的线程特性？ [英] Is it safe to mix pthread.h and C++11 standard library threading features?

问题描述

我可以用 pthread_create 产生一个线程，并安全地使用 std :: mutex 吗？

我认为如果 std :: mutex 被实现为 pthread_mutex_t 例如：

<$ p $

p> #include< pthread.h>
#include< mutex>

std :: mutex global_lock;

void * thread_func（void * vp）
{
global_lock.lock（）; // std :: mutex used in thread spawned with pthread_create
//关键部分
global_lock.unlock（）;
return NULL;
}

int main（void）
{
pthread_t tid;
pthread_create（& tid，NULL，& thread_func，NULL）; $ b $ p pthread_join（tid，NULL）;
return 0;
}


我运行Debian Wheezy。

解决方案

你可以在我的机器上（Debian太）。

如果你查看相关文件， / usr / include / c ++ / 4.7 /i486-linux-gnu/bits/gthr-default.h 在我的例子中，你会看到一个1：1映射到pthreads api。 < mutex> 使用 __ gthread_mutex_lock 锁定 pthread_mutex_lock 。或者你会看到 std :: thread 声明 typedef __gthread_t native_handle_type;

我不知道是否有一个文档化的方式来检查是否使用pthread。但 gthr-default.h 定义 _GLIBCXX_GCC_GTHR_POSIX_H 为包含警卫，我认为只要这个宏定义，假设你可以混合它们。

编辑：根据@Wakely的提示，我会写：

  template< typename T> 
 using strip = typename std :: remove_pointer< typename std :: decay< T> :: type> :: type; 
 
 static_assert（std :: is_same< strip< std :: thread :: native_handle_type>，pthread_t> :: value，
libstdc ++不使用pthread_t 
  

Can I spawn a thread with pthread_create and use std::mutex inside of it safely?

I would think that if std::mutex is implemented as a pthread_mutex_t then it would be fine but I don't see this documented anywhere

For example:

#include <pthread.h>
#include <mutex>

std::mutex global_lock;

void *thread_func(void *vp)
{
    global_lock.lock(); // std::mutex used in thread spawned with pthread_create
    //critical section
    global_lock.unlock();
    return NULL;
}

int main(void)
{
    pthread_t tid;
    pthread_create(&tid, NULL, &thread_func, NULL);
    pthread_join(tid, NULL);
    return 0;
}

BTW I'm running Debian Wheezy.

解决方案

You could on my machine (Debian too). But I'm not sure if I would call this safe.

If you look at the relevant file, /usr/include/c++/4.7/i486-linux-gnu/bits/gthr-default.h in my case, you will see that there will be a 1:1 mapping to the pthreads api. <mutex> uses __gthread_mutex_lock for locking which is defined exactly there to pthread_mutex_lock. Or you will see that std::thread declares typedef __gthread_t native_handle_type;

I don't know if there is a documented way to check if pthreads are used. But gthr-default.h defines _GLIBCXX_GCC_GTHR_POSIX_H as include guard and I think as long as this macro is defined, you can assume that you can mix them both.

Edit: Given the hint from @Wakely, I would write:

template <typename T>
using strip = typename std::remove_pointer<typename std::decay<T>::type>::type;

static_assert(std::is_same<strip<std::thread::native_handle_type>, pthread_t>::value,
              "libstdc++ doesn't use pthread_t");

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