dbus_example.c

c

#include <stdio.h>
#include <dbus/dbus.h>
#include <stdlib.h>
#include <unistd.h>

void send_signal(DBusConnection *conn) {
    DBusMessage* msg;
    DBusMessageIter args;

    msg = dbus_message_new_signal("/test/signal/Object", "test.signal.Type", "Test");
    if (NULL == msg) {
        fprintf(stderr, "Message Null\n");
        exit(1);
    }

    dbus_message_iter_init_append(msg, &args);
    char* sigvalue = "Hello from our test application!";
    if (!dbus_message_iter_append_basic(&args, DBUS_TYPE_STRING, &sigvalue)) {
        fprintf(stderr, "Out Of Memory!\n");
        exit(1);
    }

    if (!dbus_connection_send(conn, msg, NULL)) {
        fprintf(stderr, "Out Of Memory!\n");
        exit(1);
    }
    dbus_connection_flush(conn);
    printf("Signal Sent!\n");

    dbus_message_unref(msg);
}

void receive_signal(DBusConnection *conn) {
    DBusMessage* msg;
    dbus_bus_add_match(conn, "type='signal',interface='test.signal.Type'", NULL);
    dbus_connection_flush(conn);

    while (1) {
        dbus_connection_read_write(conn, 0);
        msg = dbus_connection_pop_message(conn);

        if (NULL == msg) {
            usleep(10000);
            continue;
        }

        if (dbus_message_is_signal(msg, "test.signal.Type", "Test")) {
            printf("Received Test signal with message: %s\n", dbus_message_get_member(msg));
        }

        dbus_message_unref(msg);
    }
}

int main(int argc, char** argv) {
    DBusConnection* conn;
    DBusError err;

    dbus_error_init(&err);
    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);
        return 1;
    }
    if (NULL == conn) {
        fprintf(stderr, "Connection Null\n");
        return 1;
    }

    send_signal(conn);
    receive_signal(conn);

    return 0;
}