// 
// Boost.Process 
// ~~~~~~~~~~~~~ 
// 
// Copyright (c) 2006, 2007 Julio M. Merino Vidal 
// Copyright (c) 2008 Boris Schaeling 
// 
// Distributed under the Boost Software License, Version 1.0. (See accompanying 
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) 
// 

#if defined(__CYGWIN__) 
#  define _WIN32_WINNT 0x0501 
#  define __USE_W32_SOCKETS 
#  undef BOOST_POSIX_API 
#  define BOOST_WINDOWS_API 
#endif 
#include <boost/asio.hpp> 
#define BOOST_PROCESS_WINDOWS_USE_NAMED_PIPE 
#include <boost/process.hpp> 
#include <boost/array.hpp> 
#include <boost/bind.hpp> 
#include <string> 
#include <vector> 
#include <iostream> 

namespace bp = ::boost::process; 
namespace ba = ::boost::asio; 

ba::io_service io_service; 
boost::array<char, 4096> buffer; 

#if defined(BOOST_POSIX_API) 
ba::posix::stream_descriptor in(io_service); 
#elif defined(BOOST_WINDOWS_API) 
ba::windows::stream_handle in(io_service); 
#else 
#  error "Unsupported platform." 
#endif 

bp::child start_child() 
{ 
    std::string exec = "bjam.exe"; 

    std::vector<std::string> args; 
    args.push_back("bjam.exe"); 
    args.push_back("--version"); 

    bp::context ctx; 
    ctx.stdout_behavior = bp::capture_stream(); 
    ctx.environment = bp::self::get_environment(); 

    return bp::launch(exec, args, ctx); 
} 

void end_read(const boost::system::error_code &ec, std::size_t bytes_transferred); 

void begin_read() 
{ 
    in.async_read_some(boost::asio::buffer(buffer), 
        boost::bind(&end_read, ba::placeholders::error, ba::placeholders::bytes_transferred)); 
} 

void end_read(const boost::system::error_code &ec, std::size_t bytes_transferred) 
{ 
    if (!ec) 
    { 
        std::cout << std::string(buffer.data(), bytes_transferred) << std::flush; 
        begin_read(); 
    } 
} 

int main() 
{ 
    bp::child c = start_child(); 

    bp::pistream &is = c.get_stdout(); 
    in.assign(is.handle().release()); 

    begin_read(); 
    io_service.run(); 

    c.wait(); 
}