The source will not initially be associated with any #GMainContext
and must be added to one with glib.source.Source.attach before it will be
executed.
Note that child watch sources can only be used in conjunction with
g_spawn... when the G_SPAWN_DO_NOT_REAP_CHILD flag is used.
Note that on platforms where #GPid must be explicitly closed
(see glib.global.spawnClosePid) pid must not be closed while the
source is still active. Typically, you will want to call
glib.global.spawnClosePid in the callback function for the source.
On POSIX platforms, the following restrictions apply to this API
due to limitations in POSIX process interfaces:
pid must be a child of this process
pid must be positive
the application must not call waitpid with a non-positive
first argument, for instance in another thread
the application must not wait for pid to exit by any other
mechanism, including waitpid(pid, ...) or a second child-watch
source for the same pid
the application must not ignore SIGCHLD
Before 2.78, the application could not send a signal (kill()) to the
watched pid in a race free manner. Since 2.78, you can do that while the
associated #GMainContext is acquired.
Before 2.78, even after destroying the #GSource, you could not
be sure that pid wasn't already reaped. Hence, it was also not
safe to kill() or waitpid() on the process ID after the child watch
source was gone. Destroying the source before it fired made it
impossible to reliably reap the process.
If any of those conditions are not met, this and related APIs will
not work correctly. This can often be diagnosed via a GLib warning
stating that ECHILD was received by waitpid.
Calling waitpid for specific processes other than pid remains a
valid thing to do.
Creates a new child_watch source.
The source will not initially be associated with any #GMainContext and must be added to one with glib.source.Source.attach before it will be executed.
Note that child watch sources can only be used in conjunction with g_spawn... when the G_SPAWN_DO_NOT_REAP_CHILD flag is used.
Note that on platforms where #GPid must be explicitly closed (see glib.global.spawnClosePid) pid must not be closed while the source is still active. Typically, you will want to call glib.global.spawnClosePid in the callback function for the source.
On POSIX platforms, the following restrictions apply to this API due to limitations in POSIX process interfaces:
If any of those conditions are not met, this and related APIs will not work correctly. This can often be diagnosed via a GLib warning stating that ECHILD was received by waitpid.
Calling waitpid for specific processes other than pid remains a valid thing to do.