Path: utzoo!attcan!uunet!seismo!sundc!pitstop!sun!gorodish!guy
From: guy@gorodish.Sun.COM (Guy Harris)
Newsgroups: comp.unix.questions
Subject: Re: fcntl() versus ioctl()
Keywords: FNDELAY
Message-ID: <68339@sun.uucp>
Date: 14 Sep 88 21:04:05 GMT
References: <1380@solo7.cs.vu.nl>
Sender: news@sun.uucp
Lines: 15

> Isn't it a dubious feature that the PARENT should suffer if a CHILD decides
> to set the FNDELAY flag of stdin?

Arguably.

> It's an FCNTL() we're talking about, not an IOCTL()!

The problem is that there are two sets of "file descriptor" flags: those stored
per-process, and those stored per "file table entry".  The "file table entry"
is shared by file descriptors passed to children, or created by "dup"; it holds
the seek pointer.

Unfortunately, the no-delay flag is a "file table entry" flag, not a
per-process flag.  The only per-process flag is the "close on exec" flag.
There exist "fcntl"s to manipulate both.