NAME

       sd_event_source_get_pending - Determine pending state of event sources

SYNOPSIS

       #include <systemd/sd-event.h>

       int sd_event_source_get_pending(sd_event_source *source);

DESCRIPTION

       sd_event_source_get_pending() may be used to determine whether the event source object
       specified as source has seen events but has not been dispatched yet (and thus is marked
       "pending").

       Event source objects initially are not marked pending, when they are created with calls
       such as sd_event_add_io(3), sd_event_add_time(3), with the exception of those created with
       sd_event_add_defer(3) which are immediately marked pending, and sd_event_add_exit(3) for
       which the "pending" concept is not defined. For details see the respective manual pages.

       In each event loop iteration one event source of those marked pending is dispatched, in
       the order defined by the event source priority, as set with
       sd_event_source_set_priority(3).

       For I/O event sources, as created with sd_event_add_io(3), the call
       sd_event_source_get_io_revents(3) may be used to query the type of event pending in more
       detail.

RETURN VALUE

       On success, sd_event_source_get_pending() returns an integer greater than zero when the
       event source is marked pending, and zero when the event source is not marked pending. On
       failure, it returns a negative errno-style error code.

   Errors
       Returned errors may indicate the following problems:

       -EINVAL
           source is not a valid pointer to an sd_event_source object.

       -EDOM
           source refers to an event source object created with sd_event_add_exit(3).

       -ENOMEM
           Not enough memory.

       -ESTALE
           The event loop is already terminated.

       -ECHILD
           The event loop has been created in a different process, library or module instance.

NOTES

       Functions described here are available as a shared library, which can be compiled against
       and linked to with the libsystemd pkg-config(1) file.

       The code described here uses getenv(3), which is declared to be not multi-thread-safe.
       This means that the code calling the functions described here must not call setenv(3) from
       a parallel thread. It is recommended to only do calls to setenv() from an early phase of
       the program when no other threads have been started.

HISTORY

       sd_event_source_get_pending() was added in version 229.

SEE ALSO

       sd-event(3), sd_event_add_io(3), sd_event_add_time(3), sd_event_add_signal(3),
       sd_event_add_child(3), sd_event_add_inotify(3), sd_event_add_defer(3),
       sd_event_source_unref(3)