sd_event_source_get_event — Retrieve the event loop of an event source
#include <systemd/sd-event.h>
| sd_event* sd_event_source_get_event( | sd_event_source *source ); | 
sd_event_source_get_event() may be used
    to retrieve the event loop object the event source object specified
    as source is associated with. The event
    loop object is specified when creating an event source object with
    calls such as
    sd_event_add_io(3)
    or
    sd_event_add_time(3).
On success, sd_event_source_get_event()
    returns the associated event loop object. On failure, it returns
    NULL.
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.