Get Volume of VLC over DBus

getVLCVolume.cpp

/*
g++ thisFile.cpp -I/usr/include/glib-2.0 \
                -I/usr/lib/x86_64-linux-gnu/glib-2.0/include/ \
                -lglib-2.0 -lgio-2.0 -lgobject-2.0
*/

#include <iostream>
#include <gio/gio.h>

static GMainLoop* loop = NULL;

int main()
{
    g_autoptr( GDBusConnection ) conn = NULL;
    g_autoptr( GError ) error = NULL;
    conn = g_bus_get_sync( G_BUS_TYPE_SESSION, NULL, &error );
    g_assert_no_error( error );
    if (conn == NULL)
        std::cout << "Error!" <<std::endl;

    g_autoptr( GError ) error5 = NULL;
    g_autoptr( GDBusProxy ) proxy3 = NULL;
    proxy3 = g_dbus_proxy_new_sync( conn,
                                   G_DBUS_PROXY_FLAGS_NONE, 
                                   NULL,
                                   "org.mpris.MediaPlayer2.vlc",
                                   "/org/mpris/MediaPlayer2",
                                   "org.freedesktop.DBus.Properties",
                                   NULL,
                                   &error5 );
    g_assert_no_error( error5 );
    if( proxy3 == NULL )
        std::cout << "Error!!" << std::endl;

    GVariant* ret2 = NULL;
    g_autoptr( GError ) error6 = NULL;
    ret2 =  g_dbus_proxy_call_sync( proxy3, 
                            "Get",
                            g_variant_new("(ss)", "org.mpris.MediaPlayer2.Player", "Volume"),
                            G_DBUS_CALL_FLAGS_NONE,
                            -1,
                            NULL, 
                            &error6 );
    g_assert_no_error( error6 );

    // <sorcery>
    gdouble d;
    g_assert (ret2 != NULL);
    std::cout << "Type of ret2: " << g_variant_get_type_string (ret2) << std::endl;

    GVariant* ret3 = NULL;
    ret3 = g_variant_get_child_value( ret2, 0 );
    std::cout << "Type of ret3: " << g_variant_get_type_string (ret3) << std::endl;
  

    GVariant* ret4 = NULL;
    ret4 = g_variant_get_variant( ret3 );
    std::cout << "Type of ret4: " << g_variant_get_type_string (ret4) << std::endl;
 
    //g_assert_cmpstr (g_variant_get_type_string (ret3), ==, "(d)");
    d = g_variant_get_double ( ret4 );
    //g_variant_unref (ret2);
    //g_variant_unref (ret3);
    std::cout << "Volume: " << d << std::endl;
    //</sorcery>

    return 0;    
}