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From: cthulhu@freja.diku.dk (Stefan Krabbe)
Newsgroups: comp.unix.wizards
Subject: Unblocking filedescriptor(s)
Keywords: fcntl,ioctl
Message-ID: <1991Jan25.235221.21868@odin.diku.dk>
Date: 25 Jan 91 23:52:21 GMT
Sender: news@odin.diku.dk (Netnews System)
Reply-To: cthulhu@freja.diku.dk (Stefan Krabbe)
Organization: Department of Computer Science, University of Copenhagen
Lines: 19

Hi there,
I am programming in a 4.3BSD environment. And I have a problem
I hope that somebody here can help me with. 
 In a program I am currently writing I make a filedescriptor unblocking
this way:
             fcntl(filedescriptor, F_SETFL, FNDELAY);
.. and it works just fine. But what do I do if I want it make it block-
ing again ? I have noticed that if I from within my program do
             system( ... );
 -then all my previously un-blocking filedescriptors become blocking 
again !?! If you know how to make an un-blocking filedescriptor
blocking again, then please mail me.

Best Regards
            Stefan
                                     ___
  Name:  Stefan Krabbe       .......(o o).......
  Email: cthulhu@diku.dk     ---vvv---U---vvv---
  Institute of Computer Science, University of Copenhagen.