since: 2.4


g_child_watch_add (
  GPid pid,
  GChildWatchFunc function,
  gpointer data


Sets a function to be called when the child indicated by pid exits, at a default priority, G_PRIORITY_DEFAULT.

If you obtain pid from g_spawn_async() or g_spawn_async_with_pipes() you will need to pass G_SPAWN_DO_NOT_REAP_CHILD as flag to the spawn function for the child watching to work.

Note that on platforms where GPid must be explicitly closed (see g_spawn_close_pid()) pid must not be closed while the source is still active. Typically, you will want to call g_spawn_close_pid() in the callback function for the source.

GLib supports only a single callback per process id. On POSIX platforms, the same restrictions mentioned for g_child_watch_source_new() apply to this function.

This internally creates a main loop source using g_child_watch_source_new() and attaches it to the main loop context using g_source_attach(). You can do these steps manually if you need greater control.

Available since: 2.4

This function is not directly available to language bindings.

The implementation of this method is provided by g_child_watch_add_full() in language bindings



Type: GPid

Process id to watch. On POSIX the positive pid of a child process. On Windows a handle for a process (which doesn’t have to be a child).


Type: GChildWatchFunc

Function to call.


Type: gpointer

Data to pass to function.

The argument can be NULL.
The data is owned by the caller of the function.

Return value

Type: guint

The ID (greater than 0) of the event source.