File: sd_event_source_get_pending.3

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'\" t
.TH "SD_EVENT_SOURCE_GET_PENDING" "3" "" "systemd 241" "sd_event_source_get_pending"
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.SH "NAME"
sd_event_source_get_pending \- Determine pending state of event sources
.SH "SYNOPSIS"
.sp
.ft B
.nf
#include <systemd/sd\-event\&.h>
.fi
.ft
.HP \w'int\ sd_event_source_get_pending('u
.BI "int sd_event_source_get_pending(sd_event_source\ *" "source" ");"
.SH "DESCRIPTION"
.PP
\fBsd_event_source_get_pending()\fR
may be used to determine whether the event source object specified as
\fIsource\fR
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
\fBsd_event_add_io\fR(3),
\fBsd_event_add_time\fR(3), with the exception of those created with
\fBsd_event_add_defer\fR(3)
which are immediately marked pending, and
\fBsd_event_add_exit\fR(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
\fBsd_event_source_set_priority\fR(3)\&.
.PP
For I/O event sources, as created with
\fBsd_event_add_io\fR(3), the call
\fBsd_event_source_get_io_revents\fR(3)
may be used to query the type of event pending in more detail\&.
.SH "RETURN VALUE"
.PP
On success,
\fBsd_event_source_get_pending()\fR
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\&.
.SH "ERRORS"
.PP
Returned errors may indicate the following problems:
.PP
\fB\-EINVAL\fR
.RS 4
\fIsource\fR
is not a valid pointer to an
sd_event_source
object\&.
.RE
.PP
\fB\-EDOM\fR
.RS 4
\fIsource\fR
refers to an event source object created with
\fBsd_event_add_exit\fR(3)\&.
.RE
.PP
\fB\-ENOMEM\fR
.RS 4
Not enough memory\&.
.RE
.PP
\fB\-ESTALE\fR
.RS 4
The event loop is already terminated\&.
.RE
.PP
\fB\-ECHILD\fR
.RS 4
The event loop has been created in a different process\&.
.RE
.SH "NOTES"
.PP
These APIs are implemented as a shared library, which can be compiled and linked to with the
\fBlibsystemd\fR\ \&\fBpkg-config\fR(1)
file\&.
.SH "SEE ALSO"
.PP
\fBsd-event\fR(3),
\fBsd_event_add_io\fR(3),
\fBsd_event_add_time\fR(3),
\fBsd_event_add_signal\fR(3),
\fBsd_event_add_child\fR(3),
\fBsd_event_add_inotify\fR(3),
\fBsd_event_add_defer\fR(3),
\fBsd_event_source_unref\fR(3)