sd_event_source_set_enabled, sd_event_source_get_enabled, SD_EVENT_ON, SD_EVENT_OFF, SD_EVENT_ONESHOT — Enable or disable event sources
SD_EVENT_ONESHOT= -1, };
sd_event_source_set_enabled() may be
used to enable or disable the event source object specified as
parameter takes one of
SD_EVENT_OFF (to disable) or
SD_EVENT_ONESHOT. If invoked with
SD_EVENT_ONESHOT the event source will be
enabled but automatically reset to
SD_EVENT_OFF after the event source was
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 (one of
enabled, if it is not
It also returns true if the event source is not disabled.
Event source objects are enabled when they are first created
with calls such as
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
with a prior call to
SD_EVENT_OFF, to ensure the event source is
not dispatched again until all other remaining references are dropped.
sd_event_source_set_enabled() returns a non-negative
sd_event_source_get_enabled() returns zero if the source is disabled
SD_EVENT_OFF) and a positive integer otherwise. On failure, they return a negative
errno-style error code.
These APIs are implemented as a shared
library, which can be compiled and linked to with the