yield

Yields control to event dispatching. See Eventspaces for details.

A handler procedure invoked by the system during a call to yield can itself call yield, creating an additional level of nested (but single-threaded) event handling.

See also sleep/yield .

• (yield) -> void

  Dispatches an unspecified number of events, but only if the current thread is the current eventspace's handler thread (otherwise, there is no effect).

  
  

• (yield sema) -> void
      sema : semaphore

  Blocks on sema. If the current thread is the current eventspace's handler thread, events are dispatched until a sema wait succeeds on an event boundary. For other threads, calling yield with a semaphore is equivalent to calling semaphore-wait.

  Always use (yield sema) instead of a busy-wait loop.