public class PipeTalker : Object {

        // reading callback
        private bool gio_in(IOChannel gio, IOCondition condition) {
                IOStatus ret;
                string msg;
                size_t len;

                if((condition & IOCondition.HUP) == IOCondition.HUP)
                        print("Read end of pipe died!\n");

                try {
                        ret = gio.read_line(out msg, out len, null);
                }
                catch(IOChannelError e) {
                        print("Error reading: %s\n", e.message);
                }
                catch(ConvertError e) {
                        print("Error reading: %s\n", e.message);
                }

                print("Read %u bytes: %s\n", (uint)len, msg);

                return true;
        }

        // writing callback
        private bool gio_out(IOChannel gio, IOCondition condition) {
                string msg = "The price of greatness is responsibility.\n";
                IOStatus ret;
                size_t len;

                if((condition & IOCondition.HUP) == IOCondition.HUP)
                        print("Write end of pipe died!\n");
        
                try {
                        ret = gio.write_chars((char[])msg, out len);
                }
                catch(IOChannelError e) {
                        print("Error writing: %s\n", e.message);
                }
                catch(ConvertError e) {
                        print("Error writing: %s\n", e.message);
                }

                print("Wrote %u bytes.\n", (uint)len);

                return true;
        }

        public void init_channels() {
                IOChannel io_read, io_write;
                int[] fd = new int[2]; // file descriptor
                int ret;

                // setup a pipe
                ret = Posix.pipe(fd);
                if(ret == -1) {
                        print("Creating pipe failed: %s\n", strerror(errno));
                        return;
                }
                
                // setup iochannels
                io_read  = new IOChannel.unix_new(fd[0]);
                io_write = new IOChannel.unix_new(fd[1]);
        
                if((io_read == null) || (io_write == null)) {
                        print("Cannot create new IOChannel!\n");
                        return;
                }
                
                // The watch calls the gio_in function, if there data is available for 
                // reading without locking
                if(!(io_read.add_watch(IOCondition.IN | IOCondition.HUP, gio_in) != 0)) {
                        print("Cannot add watch on IOChannel!\n");
                        return;
                }

                // The watch calls the gio_out function if there data is available for 
                // writing without locking
                if(!(io_write.add_watch(IOCondition.OUT | IOCondition.HUP, gio_out) != 0)) {
                        print("Cannot add watch on IOChannel!\n");
                        return;
                }
        }

        public static int main() {
                var loop = new MainLoop(null, false);
                var pt = new PipeTalker();
                pt.init_channels();
                loop.run();
                return 0;
        }
}