HP Advanced Communications Controllers (ACC) manual

		ZCOM C I/F Library Routines
		ZPORT (3X)
Threads	This routine may be called from multi-threaded application using the
Considerations	POSIX (1003.1c) kernel threads API package. It has the following
	characteristics when called by multi-threaded application:
	cancellation point	Thread cancellation can occur when a
		thread calls this routine.
	async-cancel unsafe	The calling thread’s cancelability
		type must be
		PTHREAD_CANCEL_DEFERRED if
		cancellation is enabled.
	async-signal unsafe	It cannot be called from a signal
		handler
	fork unsafe	It cannot be called by a child process
		after fork(2) but before exec(2).

Chapter 4 277