Connecting to systemd DBUS signals using gdbus-codegen -

i not able receive systemd dbus signals when using gdbus-codegen generated manager proxy. able call methods provided systemd on dbus.

i searched online , looked these links without success. there aren't examples on how when gdbus-codegen used systemd api.

• https://developer.gnome.org/gio/stable/gdbus-codegen.html
• http://www.freedesktop.org/software/gstreamer-sdk/data/docs/latest/gio/ch30s05.html

here did along code snippets.

1) generated systemd introspection , used xml input gdbus-codegen.

...snip

<interface name="org.freedesktop.systemd1.manager"> <signal name="jobremoved"> <arg type="u"/> <arg type="o"/> <arg type="s"/> <arg type="s"/> </signal> 

...snip

2) wrote client code use c apis generated gdbus-codegen , created manager proxy. (everything on system bus).

systemdmanager *systemdproxy = systemd_manager_proxy_new_for_bus_sync(     g_bus_type_system, g_dbus_proxy_flags_none,     "org.freedesktop.systemd1", "/org/freedesktop/systemd1",     null, error); 

3) define signal handler

static void on_done(gdbusproxy *proxy,         gchar *sender_name,         gchar *signal_name,         gvariant *parameters,         gpointer user_data) {     log_error("on_done"); } 

4) connected signal handler proxy jobremoved signal.

if (g_signal_connect(systemdproxy, "job-removed",                      g_callback(on_done), null) <= 0 ) {     log_error("failed connect signal job-removed"); } 

5) used proxy start systemd service. returns success , see unit start , run second or 2 , terminate.

ret = systemd_manager_call_start_unit_sync(     systemdproxy, unit_name, unit_mode, &job_obj,     null, &error); 

6) systemd generates jobremoved signal. dbus-monitor shows it.

signal sender=:1.0 -> dest=(null destination) serial=11931         path=/org/freedesktop/systemd1;         interface=org.freedesktop.systemd1.manager;         member=jobremoved    uint32 7009    object path "/org/freedesktop/systemd1/job/7009"    string "mysample.service"    string "done" 

7) signal handler never gets called. (everything uses system bus, there no other buses). have tried various strings detailed_signal 2nd parameter g_signal_connect (like: jobremoved, job_removed, ::job-removed, not accepted g_signal_connect).

any appreciated!

the solution use glib event loop in program. program did not have running gmainloop necessary callbacks glib. not elegant way various reasons decided spawn new thread block on g_main_loop_run. here how looks like.

void *event_loop_thread(void *unused) {     gmainloop *loop = g_main_loop_new(null, 0);     g_main_loop_run(loop); } int main() {     // snip     pthread_create(&thread_id, null, event_loop_thread, null);     // steps 2 6, , @ step 7 signal handler called } 

also had fix signal handler signature compatible signal receive meaningful parameters.

static void on_done(systemdmanager *manager,         guint32 job_id,         gchar *job_obj,         gchar *unit_name,         gchar *status) {     log_error("on_done"); }