Path: utzoo!dciem!nrcaer!cognos!brianc
From: brianc@cognos.uucp (Brian Campbell)
Newsgroups: comp.lang.c
Subject: Re: Binary I/O on stdin/stdout?
Message-ID: <2662@cognos.UUCP>
Date: 5 Apr 88 18:43:41 GMT
Article-I.D.: cognos.2662
Posted: Tue Apr  5 13:43:41 1988
References: <302@goofy.megatest.UUCP> <225800017@uxe.cso.uiuc.edu> <7550@brl-smoke.ARPA> <4250@hoptoad.uucp>
Reply-To: brianc@cognos.UUCP (Brian Campbell)
Organization: Cognos Incorporated, Ottawa, Canada
Lines: 25

In article <4250@hoptoad.uucp> gnu@hoptoad.uucp (John Gilmore) writes:
! I was just reading over the standard trying to figure out the differences
! between binary and text files and had a few realizations:
! 
!     *	Stdin, stdout, and stderr are assumed to be *text* files.
! A program that does binary I/O on them is not portable.  So, how does
! one fix this?

Is this a portable concept?

!     *   There seems to be *no way* to "reopen" these streams as
! binary.  E.g. how do I write a binary file to the current standard
! output?  Freopen will redirect stdout to a different named file, but I
! just want binary treatment for the existing output file (e.g. the one
! specified by the user when they ran "a.out >foo").

As Doug Gwyn pointed out, this makes no difference on POSIX-conforming
systems.  Under DOS, however, both the Borland and Microsoft C libraries
include a setmode(int fd, unsigned mode) function.  The mode parameter is
pretty much the same as that of creat() with the addition of two other
masks:  O_BINARY and O_TEXT.
-- 
Brian Campbell        uucp: decvax!utzoo!dciem!nrcaer!cognos!brianc
Cognos Incorporated   mail: POB 9707, 3755 Riverside Drive, Ottawa, K1G 3Z4
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