Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ncar!tank!mimsy!chris
From: chris@mimsy.UUCP (Chris Torek)
Newsgroups: comp.lang.c
Subject: Re: When to use fflush()?
Keywords: fflush
Message-ID: <19319@mimsy.UUCP>
Date: 30 Aug 89 01:34:21 GMT
References: <143@sherpa.uucp>
Distribution: na
Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742
Lines: 16

In article <143@sherpa.uucp> rac@sherpa.uucp (Roger A. Cornelius) writes:
>When should you use fflush()? OR are there any guarantees of
>when output buffers are flushed?

Output buffers are flushed by normal program exit (via exit() or
via return from main()), and, in the proposed C standard, by
`fflush((FILE *)NULL);'.  Some output buffers (those that are
`associated with terminals') are flushed by some kinds of input.

The short answer is:  Use fflush() whenever you want the output to
be visible.  Unfortunately, there is no way to simply declare that
all stdio buffers should always be fully buffered; the latter would
help efficiency, and help remind people to use fflush().
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163)
Domain:	chris@mimsy.umd.edu	Path:	uunet!mimsy!chris