x SuSE Linux 13.1-RELEASE x
x SuSE Linux 13.1-RELEASEx
SD_EVENT_SOURCE_SET_DESCsd_event_source_set_SD_EVENT_SOURCE_SET_DESCRIPTION(3)
NAME
sd_event_source_set_description, sd_event_source_get_description - Set
or retrieve descriptive names of event sources
SYNOPSIS
#include <systemd/sd-event.h>
int sd_event_source_set_description(sd_event_source *source,
const char *description);
int sd_event_source_get_description(sd_event_source *source,
const char **description);
DESCRIPTION
sd_event_source_set_description() may be used to set an arbitrary
descriptive name for the event source object specified as source. This
name will be used in debugging messages generated by sd-event(3) for
this event source, and may be queried using
sd_event_source_get_description() for debugging purposes. The
description parameter shall point to a NUL-terminated string or be
NULL. In the latter case, the descriptive name will be unset. The
string is copied internally, hence the description argument is not
referenced after the function returns.
sd_event_source_get_description() may be used to query the current
descriptive name assigned to the event source object source. It returns
a pointer to the current name in description, stored in memory internal
to the event source. The memory is invalidated when the event source is
destroyed or the descriptive name is changed.
Event source objects generally have no description set when they are
created, except for UNIX signal event sources created with
sd_event_add_signal(3), whose descriptive name is initialized to the
signal's C constant name (e.g. "SIGINT" or "SIGTERM").
RETURN VALUE
On success, sd_event_source_set_description() and
sd_event_source_get_description() return a non-negative integer. On
failure, they return 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 or the
description argument for sd_event_source_get_description() is NULL.
-ENOMEM
Not enough memory to copy the name.
-ECHILD
The event loop has been created in a different process, library or
module instance.
-ENXIO
No name was set for the event source.
NOTES
Functions described here are available as a shared library, which can
be compiled against and linked to with the libsystemd pkg-config(1)
file.
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.
SEE ALSO
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_set_userdata(3)
systemd 254 SD_EVENT_SOURCE_SET_DESCRIPTION(3)
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