Description of problem:

attempting to use the systemd-inhibitors via dbus yields no inhibition of sleep. The code doing this is below. Once called, we leave the proxy and fd open, and close them both in the "finalize" of the application. From the debug logs we see:

TI:12:24:54	TH:0x142ced0	FI:gpm-manager.c	FN:gpm_manager_systemd_inhibit,1862
 - Inhibiting systemd sleep
TI:12:24:54	TH:0x142ced0	FI:gpm-manager.c	FN:gpm_manager_systemd_inhibit,1889
 - Inhibiting systemd sleep - fd = 21537632
TI:12:24:54	TH:0x142ced0	FI:gpm-manager.c	FN:gpm_manager_systemd_inhibit,1895
 - Inhibiting systemd sleep - success


Which indicates the call is suceeding and the fd is being returned. However, running systemd-inhibt --list shows no active inhibitors. 

Advice on how to get this integration to work with systemd is much appreciated. 


    /* Return a fd to the to the inhibitor, that we can close on exit. */
	//GDBusProxy *proxy;
    GError *error = NULL;
    gint32 r = -1;

    proxy == NULL;
    /* Should we define these elsewhere? */
    const char* arg_what = "handle-power-key:handle-suspend-key:handle-lid-switch";
    const char* arg_who = "mate-power-manager";
    const char* arg_why = "Mate power manager handles these events";
    const char* arg_mode = "block";

	egg_debug ("Inhibiting systemd sleep");
    proxy = g_dbus_proxy_new_for_bus_sync (G_BUS_TYPE_SYSTEM,
                                       G_DBUS_PROXY_FLAGS_DO_NOT_LOAD_PROPERTIES,
                                        NULL,
                                        "org.freedesktop.login1",
                                        "/org/freedesktop/login1",
                                        "org.freedesktop.login1.Manager",
                                        NULL,
                                        &error );
    //append all our arguments
    if (proxy == NULL) {
        egg_error("Error connecting to dbus - %s", error->message);
        g_error_free (error);
        return -1;
    }
    r = g_dbus_proxy_call_sync (proxy, "Inhibit", 
                            g_variant_new( "(ssss)",
                                arg_what,
                                arg_who,
                                arg_why,
                                arg_mode
                            ),
                            G_DBUS_CALL_FLAGS_NONE,
                            -1,
                            NULL,
                            &error
                            );                        
	egg_debug ("Inhibiting systemd sleep - fd = %i", r);
    if (r < 1) {
        egg_error ("Error in dbus - %s", error->message);
        g_error_free (error);
        return -EIO;    
    }
    egg_debug ("Inhibiting systemd sleep - success");
    return r;