Re: [Boost-users] boost process : how to use it

Subject: Re: [Boost-users] boost process : how to use it
From: Brian Budge (brian.budge_at_[hidden])
Date: 2014-01-07 12:58:29

On Tue, Jan 7, 2014 at 8:44 AM, Vincent R. <forumer_at_[hidden]> wrote:
> Hi,
>
> What is the status of boost:process, when looking on internet you can find
> different version that are more or less compatible.
> Not an ideal situation and I am a bit surprised that this lib doesn't get
> more love from c++ dev.
> Anyway after a long time coding in easier language I decided to do a small
> project under linux that consists in a tcp server running
> on linux that start some process initiated by a client and sends the output.
> So I have downaloaded the most "official" version I could find here
> http://www.highscore.de/boost/process/ and I tried the following code :
>
> #include <cassert>
> #include <iostream>
> #include <map>
> #include <string>
> #include <sstream>
> #include <vector>
> #include <boost/asio.hpp>
> #include <boost/enable_shared_from_this.hpp>
> #include <boost/process.hpp>
>
> namespace asio = boost::asio;
> namespace bp = boost::process;
> using asio::ip::tcp;
>
>
> bp::child start_child()
> {
>     std::string exec = boost::process::find_executable_in_path("dpkg");
>     std::vector<std::string> args;
>     args.push_back("-l");
>
>     bp::context ctx;
>     ctx.stderr_behavior = bp::capture_stream();
>
>     return bp::launch(exec, args, ctx);
> }
>
>
> int main(int argc, char *argv[])
> {
>     std::string value;
>
>     bp::child c = start_child();
>     bp::pistream &is = c.get_stderr();
>     std::string line;
>     while (std::getline(is, line))
>     {
>         value += line + "\r\n";
>     }
>     c.wait();
>
>     std::cout << "OUTPUT: " << value << std::endl;
>
>
>    return 0;
> }
>
> My first question is how can I merge the stderr with stdout because some
> commands use stdout and some others stderr ?
>
> My second question is : why the code above doesn't work properly and doesn't
> handle the arguments I am passing ?
> Indeed when I run the code I get the following output :
>
> OUTPUT: dpkg: error: need an action option
>
> it means that the -l is not taken in consideration.
>
> Thanks for any help
>
>
>
>
>
>
>
>
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> Boost-users_at_[hidden]
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For what its worth, this is the more recent version:
http://www.highscore.de/boost/process0.5/

  Brian