x SuSE Linux 13.1-RELEASE x
x SuSE Linux 13.1-RELEASEx
SD_EVENT_SOURCE_SET_USERDsd_event_source_set_usSD_EVENT_SOURCE_SET_USERDATA(3)
NAME
sd_event_source_set_userdata, sd_event_source_get_userdata - Set or
retrieve user data pointer of event sources
SYNOPSIS
#include <systemd/sd-event.h>
void* sd_event_source_set_userdata(sd_event_source *source,
void *userdata);
void* sd_event_source_get_userdata(sd_event_source *source);
DESCRIPTION
sd_event_source_set_userdata() may be used to set an arbitrary user
data pointer for the event source object specified as source. The user
data pointer is usually specified when creating an event source object
with calls such as sd_event_add_io(3) or sd_event_add_time(3), and may
be updated with this call. The user data pointer is also passed to all
handler callback functions associated with the event source. The
userdata parameter specifies the new user data pointer to set, the
function returns the previous user data pointer. Note that NULL is a
valid user data pointer.
sd_event_source_get_userdata() may be used to query the current user
data pointer assigned to the event source object source.
RETURN VALUE
On success, sd_event_source_set_userdata() and
sd_event_source_get_userdata() return the previously set user data
pointer. On failure, they return NULL.
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_description(3)
systemd 254 SD_EVENT_SOURCE_SET_USERDATA(3)
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