如何使用C ++ libboost运行进程并获取其输出? [英] How to run a process and get its output using c++ libboost?

问题描述

我正在尝试运行外部Shell命令并使用C ++的Boost库读取其输出，但是似乎该命令未运行或者我无法访问输出.我正在使用其文档作为示例，并这样写:

I'm trying to run an external shell command and read its output using the Boost libraries for C++ but it seems that either the command is not running or I just can't access the output. I'm using their documentation as example and wrote this:

#include <boost/process.hpp>
namespace bp = boost::process;

bool is_process_running(std::string p_name){
        string cmd = "ps aux 2>&1";
        bp::ipstream out;
        std::string line;
        bp::child c(cmd, bp::std_out > out);

        // the while is supposed to read each line of the output
        // but the execution doesn't enter here
        while(c.running() && std::getline(out, line) && !line.empty())
        {
            if(line.find(p_name) != std::string::npos)
            {
                return true;
            }
        }
        c.wait();
        return false;
}

目标是验证ps aux的每一行输出并搜索进程是否正在运行.那么，这里可能是什么问题呢?或者，您可以为此提供一个简单的代码段吗?

The goal is to verify each line output of ps aux and search if a process is running. So, what could be the problem here? Or, can you provide a simple snippet for doing this?

推荐答案

只需使用shell(或使用bp::system):

Simply use a shell (or use bp::system):

在Coliru上直播

#include <boost/process.hpp>
namespace bp = boost::process;

bool is_process_running(std::string p_name){
    std::vector<std::string> args { "-c", "ps aux 2>&1" };
    bp::ipstream out;
    bp::child c(bp::search_path("sh"), args, bp::std_out > out);

    for (std::string line; c.running() && std::getline(out, line);) {
        if (line.find(p_name) != std::string::npos) {
            return true;
        }
    }
    c.wait();

    return false;
}

#include <iostream>
int main() {
    std::cout << "bogus: " << is_process_running("bogus") << "\n";
    std::cout << "a.out: " << is_process_running("a.out") << "\n";
}

打印

bogus: 0
a.out: 1

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