This example is part of a series of examples that demonstrate signal emission/handling in a variety of ways. This group of examples are:
signal_emitter_c.cpp
- Signal emission with the dbus C API signal_emitter_raw.cpp
- Signal emission with a manually created message signal_emitter.cpp
- Signal emission with a DBus::signal signal_emitter_2.cpp
- Signal emission with a DBus::signal and a local connection as well signal_emitter_3.cpp
- Dispatched signal emission and a local connection signal_emitter_object.cpp
- Signal emission with a DBus::Object derived class signal_receiver_c.cpp
- Signal handling with the dbus C API signal_receiver_raw.cpp
- Signal handling with a manual loop similar to the C API example signal_receiver.cpp
- Signal handling with a dispatcher and raw DBus signal demarshalling signal_receiver_2.cpp
- Signal handling with a dispatcher and automatic demarshalling signal_receiver_object.cpp
- Signal handling with a DBus::ObjectProxy derived class Here is this example:
/*************************************************************************** * Copyright (C) 2007,2008,2009 by Rick L. Vinyard, Jr. * * rvinyard@cs.nmsu.edu * * * * This file is part of the dbus-cxx library. * * * * The dbus-cxx library is free software; you can redistribute it and/or * * modify it under the terms of the GNU General Public License * * version 3 as published by the Free Software Foundation. * * * * The dbus-cxx library is distributed in the hope that it will be * * useful, but WITHOUT ANY WARRANTY; without even the implied warranty * * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * * General Public License for more details. * * * * You should have received a copy of the GNU General Public License * * along with this software. If not see <http://www.gnu.org/licenses/>. * ***************************************************************************/ #include <dbus/dbus.h> #include <stdio.h> #include <unistd.h> int main() { DBusError err; DBusConnection* conn; int ret; // initialise the errors dbus_error_init( &err ); // connect to the bus conn = dbus_bus_get( DBUS_BUS_SESSION, &err ); if ( dbus_error_is_set( &err ) ) { fprintf( stderr, "Connection Error (%s)\n", err.message ); dbus_error_free( &err ); } if ( NULL == conn ) { return( 1 ); } char* sigvalue; DBusMessage * msg; DBusMessageIter args; // add a rule for which messages we want to see dbus_bus_add_match( conn, "type='signal',interface='test.signal.Type'", &err ); // see signals from the given interface dbus_connection_flush( conn ); if ( dbus_error_is_set( &err ) ) { fprintf( stderr, "Match Error (%s)\n", err.message ); return( 1 ); } // loop listening for signals being emmitted while ( true ) { // non blocking read of the next available message dbus_connection_read_write( conn, 0 ); msg = dbus_connection_pop_message( conn ); // loop again if we haven't read a message if ( NULL == msg ) { sleep( 1 ); continue; } // check if the message is a signal from the correct interface // and with the correct name if ( dbus_message_is_signal( msg, "test.signal.Type", "Test" ) ) { // read the parameters if ( !dbus_message_iter_init( msg, &args ) ) fprintf( stderr, "Message has no arguments!\n" ); else if ( DBUS_TYPE_STRING != dbus_message_iter_get_arg_type( &args ) ) fprintf( stderr, "Argument is not string!\n" ); else { dbus_message_iter_get_basic( &args, &sigvalue ); printf( "Got Signal with value %s\n", sigvalue ); } } // free the message dbus_message_unref( msg ); } }