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From: brnstnd@stealth.acf.nyu.edu
Newsgroups: comp.unix.questions
Subject: Re: How to do a non-blocking write of more than one char?
Message-ID: <5564@stealth.acf.nyu.edu>
Date: 10 Jan 90 22:23:33 GMT
References: <2759@stealth.acf.nyu.edu> <2799@auspex.auspex.com>
Reply-To: brnstnd@stealth.acf.nyu.edu (Dan Bernstein)
Distribution: usa
Organization: IR
Lines: 24

In article <2799@auspex.auspex.com> guy@auspex.auspex.com (Guy Harris) writes:
> It's
> guaranteed that you can write *some* amount of data without blocking,
> but no guarantee as to how much is made, in general.

Can you show me a program that blocks on a write() after select() has
indicated that the descriptor is writable? (select() on this machine
is slightly buggy, so I'm not sure my tests are accurate.)

> Sorry, but you
> really *are* expected to use non-blocking I/O in that case.... 

Okay, Guy, tell me how I accomplish this: Process A writes data to a
pipe connected to Process B. Process A must not block on its writes,
because it has to handle other descriptors as well. Process B is an
already-written program that assumes that its reads are non-blocking;
it'll take EWOULDBLOCK as a read error and die horribly.

Process A can avoid blocking by using select() and writing just one
character at a time. Is there any other way?

C'mon, guys, this is a simple question!

---Dan