How to distinguish between STREAMS and non-STREAMSD

Keith Holder khh at root.co.uk
Fri Jan 25 22:10:41 AEST 1991


>josef at nixpbe.nixdorf.de (josef Moellers) writes:
>>Does anybody now of a bulletproof and FAST method to distinguish between
>>a STREAMS fd and a non-STREAMS fd?
>>I cannot use calls to getmsg/putmsg, as I am not allowed to change the
>>state of the STREAM.

In System V Release 4, there is a library function called isastream(3C), which 
takes a file descriptor as an argument. It returns 1 if fildes represents a
STREAMS file, 0 if not. It behaves very much like  isatty().
	I don't know whether this function was available in previous releases.
-- 
--
Keith Holder, Systems Software Consultant, UniSoft Ltd.
<khh at root.co.uk>	G1ITH	Fax:	(071) 729 3273
Phone:	+44 71 729 3773 



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