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Diffstat (limited to 'upstream/fedora-40/man3/sd-event.3')
| -rw-r--r-- | upstream/fedora-40/man3/sd-event.3 | 222 |
1 files changed, 222 insertions, 0 deletions
diff --git a/upstream/fedora-40/man3/sd-event.3 b/upstream/fedora-40/man3/sd-event.3 new file mode 100644 index 00000000..b90da13b --- /dev/null +++ b/upstream/fedora-40/man3/sd-event.3 @@ -0,0 +1,222 @@ +'\" t +.TH "SD\-EVENT" "3" "" "systemd 255" "sd-event" +.\" ----------------------------------------------------------------- +.\" * Define some portability stuff +.\" ----------------------------------------------------------------- +.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +.\" http://bugs.debian.org/507673 +.\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html +.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +.ie \n(.g .ds Aq \(aq +.el .ds Aq ' +.\" ----------------------------------------------------------------- +.\" * set default formatting +.\" ----------------------------------------------------------------- +.\" disable hyphenation +.nh +.\" disable justification (adjust text to left margin only) +.ad l +.\" ----------------------------------------------------------------- +.\" * MAIN CONTENT STARTS HERE * +.\" ----------------------------------------------------------------- +.SH "NAME" +sd-event \- A generic event loop implementation +.SH "SYNOPSIS" +.sp +.ft B +.nf +#include <systemd/sd\-event\&.h> +.fi +.ft +.HP \w'\fBpkg\-config\ \-\-cflags\ \-\-libs\ libsystemd\fR\ 'u +\fBpkg\-config \-\-cflags \-\-libs libsystemd\fR +.SH "DESCRIPTION" +.PP +sd\-event\&.h +is part of +\fBlibsystemd\fR(3) +and provides a generic event loop implementation, based on Linux +\fBepoll\fR(7)\&. +.PP +See +\fBsd_event_new\fR(3), +\fBsd_event_run\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_add_memory_pressure\fR(3), +\fBsd_event_source_unref\fR(3), +\fBsd_event_source_set_priority\fR(3), +\fBsd_event_source_set_enabled\fR(3), +\fBsd_event_source_set_userdata\fR(3), +\fBsd_event_source_get_event\fR(3), +\fBsd_event_source_get_pending\fR(3), +\fBsd_event_source_set_description\fR(3), +\fBsd_event_source_set_prepare\fR(3), +\fBsd_event_source_set_ratelimit\fR(3), +\fBsd_event_wait\fR(3), +\fBsd_event_get_fd\fR(3), +\fBsd_event_set_watchdog\fR(3), +\fBsd_event_exit\fR(3), +\fBsd_event_now\fR(3) +for more information about the functions available\&. +.PP +The event loop design is targeted on running a separate instance of the event loop in each thread; it has no concept of distributing events from a single event loop instance onto multiple worker threads\&. Dispatching events is strictly ordered and subject to configurable priorities\&. In each event loop iteration a single event source is dispatched\&. Each time an event source is dispatched the kernel is polled for new events, before the next event source is dispatched\&. The event loop is designed to honor priorities and provide fairness within each priority\&. It is not designed to provide optimal throughput, as this contradicts these goals due the limitations of the underlying +\fBepoll\fR(7) +primitives\&. +.PP +The event loop implementation provides the following features: +.sp +.RS 4 +.ie n \{\ +\h'-04' 1.\h'+01'\c +.\} +.el \{\ +.sp -1 +.IP " 1." 4.2 +.\} +I/O event sources, based on +\fBepoll\fR(7)\*(Aqs file descriptor watching, including edge triggered events (\fBEPOLLET\fR)\&. See +\fBsd_event_add_io\fR(3)\&. +.RE +.sp +.RS 4 +.ie n \{\ +\h'-04' 2.\h'+01'\c +.\} +.el \{\ +.sp -1 +.IP " 2." 4.2 +.\} +Timer event sources, based on +\fBtimerfd_create\fR(2), supporting the +\fBCLOCK_MONOTONIC\fR, +\fBCLOCK_REALTIME\fR, +\fBCLOCK_BOOTTIME\fR +clocks, as well as the +\fBCLOCK_REALTIME_ALARM\fR +and +\fBCLOCK_BOOTTIME_ALARM\fR +clocks that can resume the system from suspend\&. When creating timer events a required accuracy parameter may be specified which allows coalescing of timer events to minimize power consumption\&. See +\fBsd_event_add_time\fR(3)\&. +.RE +.sp +.RS 4 +.ie n \{\ +\h'-04' 3.\h'+01'\c +.\} +.el \{\ +.sp -1 +.IP " 3." 4.2 +.\} +UNIX process signal events, based on +\fBsignalfd\fR(2), including full support for real\-time signals, and queued parameters\&. See +\fBsd_event_add_signal\fR(3)\&. +.RE +.sp +.RS 4 +.ie n \{\ +\h'-04' 4.\h'+01'\c +.\} +.el \{\ +.sp -1 +.IP " 4." 4.2 +.\} +Child process state change events, based on +\fBwaitid\fR(2)\&. See +\fBsd_event_add_child\fR(3)\&. +.RE +.sp +.RS 4 +.ie n \{\ +\h'-04' 5.\h'+01'\c +.\} +.el \{\ +.sp -1 +.IP " 5." 4.2 +.\} +Static event sources, of three types: defer, post and exit, for invoking calls in each event loop, after other event sources or at event loop termination\&. See +\fBsd_event_add_defer\fR(3)\&. +.RE +.sp +.RS 4 +.ie n \{\ +\h'-04' 6.\h'+01'\c +.\} +.el \{\ +.sp -1 +.IP " 6." 4.2 +.\} +Event sources may be assigned a 64\-bit priority value, that controls the order in which event sources are dispatched if multiple are pending simultaneously\&. See +\fBsd_event_source_set_priority\fR(3)\&. +.RE +.sp +.RS 4 +.ie n \{\ +\h'-04' 7.\h'+01'\c +.\} +.el \{\ +.sp -1 +.IP " 7." 4.2 +.\} +The event loop may automatically send watchdog notification messages to the service manager\&. See +\fBsd_event_set_watchdog\fR(3)\&. +.RE +.sp +.RS 4 +.ie n \{\ +\h'-04' 8.\h'+01'\c +.\} +.el \{\ +.sp -1 +.IP " 8." 4.2 +.\} +The event loop may be integrated into foreign event loops, such as the GLib one\&. See +\fBsd_event_get_fd\fR(3) +for an example\&. +.RE +.SH "NOTES" +.PP +Functions described here are available as a shared library, which can be compiled against and linked to with the +\fBlibsystemd\fR\ \&\fBpkg-config\fR(1) +file\&. +.PP +The code described here uses +\fBgetenv\fR(3), which is declared to be not multi\-thread\-safe\&. This means that the code calling the functions described here must not call +\fBsetenv\fR(3) +from a parallel thread\&. It is recommended to only do calls to +\fBsetenv()\fR +from an early phase of the program when no other threads have been started\&. +.SH "SEE ALSO" +.PP +\fBsystemd\fR(1), +\fBsd_event_new\fR(3), +\fBsd_event_run\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_add_memory_pressure\fR(3), +\fBsd_event_source_unref\fR(3), +\fBsd_event_source_set_priority\fR(3), +\fBsd_event_source_set_enabled\fR(3), +\fBsd_event_source_set_userdata\fR(3), +\fBsd_event_source_get_event\fR(3), +\fBsd_event_source_get_pending\fR(3), +\fBsd_event_source_set_description\fR(3), +\fBsd_event_source_set_prepare\fR(3), +\fBsd_event_source_set_ratelimit\fR(3), +\fBsd_event_wait\fR(3), +\fBsd_event_get_fd\fR(3), +\fBsd_event_set_watchdog\fR(3), +\fBsd_event_exit\fR(3), +\fBsd_event_now\fR(3), +\fBepoll\fR(7), +\fBtimerfd_create\fR(2), +\fBsignalfd\fR(2), +\fBwaitid\fR(2) |