systemd/man/sd_event_run.3
2015-05-25 11:04:44 +02:00

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3.6 KiB
Groff

'\" t
.TH "SD_EVENT_RUN" "3" "" "systemd 220" "sd_event_run"
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.SH "NAME"
sd_event_run, sd_event_loop \- Run libsystemd event loop
.SH "SYNOPSIS"
.sp
.ft B
.nf
#include <systemd/sd\-event\&.h>
.fi
.ft
.HP \w'int\ sd_event_run('u
.BI "int sd_event_run(sd_event\ *" "event" ", uint64_t\ " "timeout" ");"
.HP \w'int\ sd_event_loop('u
.BI "int sd_event_loop(sd_event\ *" "event" ");"
.SH "DESCRIPTION"
.PP
\fBsd_event_run()\fR
can be used to run one iteration of the event loop of libsystemd\&. This function waits until an event to process is available and dispatches a handler for it\&. Parameter
\fItimeout\fR
specifices the maximum time (in microseconds) to wait\&.
\fB(uint64_t) \-1\fR
may be used to specify an infinite timeout\&.
.PP
\fBsd_event_loop\fR
runs
\fBsd_event_wait\fR
in a loop with a timeout of infinity\&. This makes it suitable for the main event loop of a program\&.
.PP
The event loop object
\fIevent\fR
is created with
\fBsd_event_new\fR\&. Events to wait for and their handlers can be registered with
\fBsd_event_add_time\fR,
\fBsd_event_add_child\fR,
\fBsd_event_add_signal\fR,
\fBsd_event_add_defer\fR,
\fBsd_event_add_exit\fR, and
\fBsd_event_add_post\fR\&.
.PP
For more fine\-grained control,
\fBsd_event_prepare\fR,
\fBsd_event_wait\fR, and
\fBsd_event_dispatch\fR
may be used\&. Along with
\fBsd_event_get_fd\fR, those functions make it possible to integrate the libsystemd loop inside of another event loop\&.
.SH "RETURN VALUE"
.PP
On success, these functions return 0 or a positive integer\&. On failure, they return a negative errno\-style error code\&.
\fBsd_event_run\fR
returns 0 if the event loop is finished, and a positive value if it can be continued\&.
.SH "ERRORS"
.PP
Returned errors may indicate the following problems:
.PP
\fB\-EINVAL\fR
.RS 4
Parameter
\fIevent\fR
is
\fBNULL\fR\&.
.RE
.PP
\fB\-EBUSY\fR
.RS 4
The event loop object is not in the right state (see
\fBsd_event_prepare\fR(3)
for an explanation of possible states)\&.
.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
.PP
Other errors are possible too\&.
.SH "NOTES"
.PP
\fBsd_event_run()\fR
and
\fBsd_event_loop()\fR
are available as a shared library, which can be compiled and linked to with the
\fBlibsystemd\fR\ \&\fBpkg-config\fR(1)
file\&.
.SH "SEE ALSO"
.PP
\fBsystemd\fR(1),
\fBsd_event_new\fR(3),
\fBsd_event_wait\fR(3),
\fBsd_event_add_io\fR(3),
\fBsd_event_add_time\fR(3),
\fBsd_event_add_signal\fR(3),
\fBsd_event_add_defer\fR(3),
\fBsd_event_add_exit\fR(3),
\fBsd_event_add_post\fR(3),
\m[blue]\fBGLIb Main Event Loop\fR\m[]\&\s-2\u[1]\d\s+2\&.
.SH "NOTES"
.IP " 1." 4
GLIb Main Event Loop
.RS 4
\%https://developer.gnome.org/glib/unstable/glib-The-Main-Event-Loop.html
.RE