Re: [Boost-users] [Asio] Need help making a custom service

Subject: Re: [Boost-users] [Asio] Need help making a custom service
From: Kyle Edwards (kedwards_at_[hidden])
Date: 2015-03-16 09:18:06

Haven't tested it, but at first glance it looks correct.

So you don't think there's a need to implement service and all that,
like I did in my code?

Kyle

On Mon, 2015-03-16 at 12:27 +0100, svante karlsson wrote:
> Sorry for not replying earlier but I have not yet gotten any time to
> actually try it out on a raspberry.
> 
> 
> Hopefully tonight.... anyway - if the original code worked then the
> following "could"  there is probably mistakes since I compiled this on
> windows and the ::open call in not working there... 
> 
> 
> 
> 
>                 #include <fcntl.h>
>                 #include <iostream>
>                 #include <boost/bind.hpp>
>                 #include <boost/thread.hpp>
>                 #include <boost/asio.hpp>
>                 #include <boost/function.hpp>
>                 
>                 class gpio_interrupt
>                 {
>                 public:
>                     gpio_interrupt(boost::asio::io_service &ios,
>                 unsigned int number) : 
>                         _socket(ios)
>                     {
>                         open(number);
>                     }
>                 
>                     ~gpio_interrupt()
>                     {
>                         close();
>                     }
>                 
>                     void open(unsigned int number)
>                     {
>                         boost::system::error_code ec;
>                         open(number, ec);
>                         boost::asio::detail::throw_error(ec, "open");
>                     }
>                 
>                     void open(unsigned int number,
>                 boost::system::error_code& ec)
>                     {
>                         std::ostringstream filename;
>                         filename << "/sys/class/gpio/gpio" << number
>                 << "/value";
>                 
>                         int fd = ::open(filename.str().c_str(),
>                 O_RDONLY | O_NONBLOCK);
>                         if (fd < 0)
>                         {
>                             ec = boost::system::error_code(errno,
>                 boost::asio::error::get_system_category());
>                             return;
>                         }
>                         _socket.assign(boost::asio::ip::udp::v4(), fd,
>                 ec);
>                     }
>                 
>                     void close()
>                     {
>                         boost::system::error_code ec;
>                         cancel(ec);
>                         boost::asio::detail::throw_error(ec, "close");
>                     }
>                 
>                     void close(boost::system::error_code& ec)
>                     {
>                         cancel(ec);
>                     }
>                 
>                     void cancel()
>                     {
>                         boost::system::error_code ec;
>                         _socket.cancel(ec);
>                         boost::asio::detail::throw_error(ec, "close");
>                     }
>                 
>                     void cancel(boost::system::error_code& ec)
>                     {
>                         _socket.cancel(ec);
>                     }
>                 
>                     void async_wait(boost::function<void(const
>                 boost::system::error_code& ec)> cb)
>                     {
>                 
>                 _socket.async_receive(boost::asio::null_buffers(),
>                 [cb](const boost::system::error_code& ec, std::size_t
>                 bytes_transferred)
>                         {
>                             cb(ec);
>                         });
>                     }
>                 
>                 private:
>                     boost::asio::ip::udp::socket    _socket;
>                 };
>                 
>                 
>                 int main(int argc, char **argv)
>                 {
>                     boost::asio::io_service ios;
>                     boost::asio::io_service::work work(ios);
>                     boost::thread
>                 thread(boost::bind(&boost::asio::io_service::run,
>                 &ios));
>                 
>                     gpio_interrupt interrupt(ios, 21);
>                     interrupt.async_wait([](const
>                 boost::system::error_code& ec)
>                     {
>                         if (ec)
>                         {
>                             std::cout << ec.message() << std::endl;
>                             return;
>                         }
>                 
>                         std::cout << "Pin changed state" << std::endl;
>                     });
>                 
>                     while (true)
>                     {
>                 
>                 boost::this_thread::sleep(boost::posix_time::milliseconds(1000));  // just dummy - do something else here...
>                     }
>                     
>                     ios.stop();
>                     thread.join();
>                     return 0;
>                 }
> 
> 
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