| SD_EVENT_SOURCE_GET_PENDING(3) | sd_event_source_get_pending | SD_EVENT_SOURCE_GET_PENDING(3) |
.SH "NAME" sd_event_source_get_pending - Determine pending state of
event sources
.SH "SYNOPSIS"
#include <systemd/sd-event.h>
.HP 768u int
sd_event_source_get_pending(sd_event_source *source);
.SH "DESCRIPTION"
.PP 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").
.PP 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.
.PP 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).
.PP 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.
.SH "RETURN VALUE"
.PP 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.
.SS "Errors"
.PP Returned errors may indicate the following problems:
.PP -EINVAL
source is not a valid pointer to an sd_event_source object.
.RE
.PP -EDOM
source refers to an event source object created with
sd_event_add_exit(3).
.RE
.PP -ENOMEM
Not enough memory.
.RE
.PP -ESTALE
The event loop is already terminated.
.RE
.PP -ECHILD
The event loop has been created in a different process, library or module
instance.
.RE
.SH "NOTES"
.PP Functions described here are available as a shared library, which can be
compiled against and linked to with the
libsystemd pkg-config(1) file.
.PP All functions listed here are thread-agnostic and only a single thread
may operate on a given object at any given time. Different threads may
access the same object at different times. Multiple independent objects may
be used from different threads in parallel.
.PP 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.
.SH "HISTORY"
.PP sd_event_source_get_pending() was added in version 229.
.SH "SEE ALSO"
.PP 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)
| systemd 262.2 |