NAME

sd_event_source_get_pending - Determine pending state of event sources

SYNOPSIS

#include <elogind/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.

NOTES

These APIs are implemented as a shared library, which can be compiled and linked to with the libelogind pkg-config(1) file.