Other Alias
sd_event_source_set_enabled, SD_EVENT_ON, SD_EVENT_OFF, SD_EVENT_ONESHOTSYNOPSIS
#include <systemd/sd-event.h>
enum {
SD_EVENT_OFF = 0,
SD_EVENT_ON = 1,
SD_EVENT_ONESHOT = -1,
};
-
int sd_event_source_set_enabled(sd_event_source *source, int enabled);
- int sd_event_source_get_enabled(sd_event_source *source, int *enabled);
DESCRIPTION
sd_event_source_set_enabled()
Event sources that are disabled will not result in event loop wakeups and will not be dispatched, until they are enabled again.
sd_event_source_get_enabled() may be used to query whether the event source object source is currently enabled or not. It returns the enablement state in enabled.
Event source objects are enabled when they are first created with calls such as sd_event_add_io(3), sd_event_add_time(3). However, depending on the event source type they are enabled continuously (SD_EVENT_ON) or only for a single invocation of the event source handler (SD_EVENT_ONESHOT). For details see the respective manual pages.
As event source objects stay active and may be dispatched as long as there is at least one reference to them, in many cases it is a good idea to combine a call to sd_event_source_unref(3) with a prior call to sd_event_source_set_enabled() with SD_EVENT_OFF, to ensure the event source is not dispatched again until all other remaining references are dropped.
RETURN VALUE
On success, sd_event_source_set_enabled() and sd_event_source_get_enabled() 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.
-ENOMEM
- Not enough memory.
-ECHILD
- The event loop has been created in a different process.
NOTES
These APIs are implemented as a shared library, which can be compiled and linked to with the libsystemd pkg-config(1) file.