C ++标准支持进程吗？ [英] Does the C++ standard support processes?

问题描述

我知道C ++ 11增加了对线程的支持。例如：

  #include< iostream> 
 #include< thread> 
 
 void bar（）
 {
 std :: cout< 谷仓; 
} 
 
 int main（）
 {
 std :: thread thread（bar）; 
 thread.join（）; 
 
 return 0; 
} 
  

但是，有没有办法执行 在单独的进程中的功能？

注意：我知道使用平台的可能性独立的库，我只是好奇，如果C + +支持这个直接或将来。

解决方案

不，c ++标准特别是C ++ 11）没有任何过程的概念（因此我不能给你一个更合理的引用，作为搜索结果来自最流行的和当前最新的c ++文档网站） p>

我也不知道过程支持计划用于下一个标准版本C ++ - 17（aka C ++ - 1z）。至少维基百科网站没有提及。

有一个流行的实现是为了提升，

你通常不能写可移植代码在裸机系统上运行，只有一个进程

em>存在。

---

但是，有没有办法执行 bar（）函数在一个单独的进程？

最简单的选项是备份到 fork（） 和 wait（） ：

  #include< iostream> 
 #include< unistd.h> 
 #include< sys / wait.h> 
 
 void bar（）
 {
 std :: cout< 谷仓; 
} 
 
 int main（int argc，char ** argv）
 {
 pid_t pid = fork（）; 
 
 if（pid == 0）
 {
 //子进程
 bar（）; 
} 
 else if（pid> 0）
 {
 //父进程
 wait（NULL）; 
} 
 else 
 {
 // fork failed 
 std :: cerr<< fork（）failed！ << std :: endl; 
 return 1; 
} 
 
 
 return 0; 
} 
  

---

看到许多点，创建一个额外的过程来执行一个简单的函数。在这种情况下，创建一个进程会产生很多不需要的开销。

好吧，如果你想使用 exec（）函数系列是一个不同的用例。

我建议坚持使用 std :: thread s。

I know C++11 added support for threads. For example:

#include <iostream>
#include <thread>

void bar()
{
    std::cout << "bar()\n";
}

int main()
{
    std::thread thread(bar);
    thread.join();

    return 0;
}

However, is there a way to execute the bar function in a separate process? If not, is there any discussion on whether such a feature should be added?

Note: I'm aware of the possibility of using platform independent libraries and I'm just curious if C++ supports this directly or will in the future.

解决方案

No, the c++ standard (particularly C++11) doesn't have any notion of a process (hence I can't give you a more reasonable reference here as a search result from the most popular and currently most up to date c++ documentation site).

I'm also not aware that process support is planned for the next standard version C++-17 (aka C++-1z). At least the Wikipedia Site doesn't mention it.

There is a popular implementation that was proposed for boost, but that never was drawn for a C++ standard proposal.

You usually can't write portable code to run on bare metal systems, where only one process exists.

---

However, is there a way to execute the bar() function in a separate process?

The simplest option to do that is to fallback to fork() and wait() as specified by the POSIX Open Group:

#include <iostream>
#include <unistd.h>
#include <sys/wait.h>

void bar()
{
    std::cout << "bar()\n";
}    

int main(int argc, char **argv)
{
    pid_t pid = fork();

    if (pid == 0)
    {
        // child process
        bar();
    }
    else if (pid > 0)
    {
        // parent process
        wait(NULL);    
    }
    else
    {
        // fork failed
        std::cerr << "fork() failed!" << std::endl;
        return 1;
    }


    return 0;
}

---

Though I don't see much of a point to create an extra process to execute a simple function. Creating a process creates a lot of overhead you don't want in such case.

Well, if you want to start another program using functions from the exec() function family that's a different use case.

I'd recommend sticking to std::threads for your example.

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