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

Subject: Re: [Boost-users] [Asio] Need help making a custom service
From: svante karlsson (saka_at_[hidden])
Date: 2015-03-16 07:27:37

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;
>
> }
>
>