Xref: utzoo unix-pc.general:2203 comp.sys.att:5483
Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ncar!ames!lll-lcc!pyramid!cbmvax!ditto
From: ditto@cbmvax.UUCP (Michael "Ford" Ditto)
Newsgroups: unix-pc.general,comp.sys.att
Subject: Re: termio(7) and read(2) problem!
Summary: fcntl()
Keywords: NDELAY
Message-ID: <5929@cbmvax.UUCP>
Date: 9 Feb 89 03:33:34 GMT
References: <137@zebra.UUCP> <7411@chinet.chi.il.us> <10652@stb.UUCP>
Reply-To: ditto@cbmvax.UUCP (Michael "Ford" Ditto)
Organization: Commodore Technology, West Chester, PA
Lines: 23

In article <10652@stb.UUCP> michael@stb.UUCP (Michael) writes:
>Does anyone know how to turn ON NDELAY for an already open file?

Use fcntl(2):

	int oldmode = fcntl(fd, F_GETFL);
	if (oldmode == -1)
	    perror("fcntl(F_GETFL)");
	else
	    if (fcntl(fd, F_SETFL, oldmode|O_NDELAY) == -1)
		perror("fcntl(F_SETFL)");

Or, if you're not a fan of error checking:

	fcntl(fd, F_SETFL, fcntl(fd, F_GETFL)|O_NDELAY);

-- 
					-=] Ford [=-

"The number of Unix installations	(In Real Life:  Mike Ditto)
has grown to 10, with more expected."	ford@kenobi.cts.com
- The Unix Programmer's Manual,		...!sdcsvax!crash!elgar!ford
  2nd Edition, June, 1972.		ditto@cbmvax.commodore.com