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From: mouse@mcgill-vision.UUCP
Newsgroups: net.lang.c
Subject: Re: Missing stdio features.
Message-ID: <479@mcgill-vision.UUCP>
Date: Sat, 9-Aug-86 06:35:33 EDT
Article-I.D.: mcgill-v.479
Posted: Sat Aug  9 06:35:33 1986
Date-Received: Tue, 12-Aug-86 15:12:16 EDT
References: <2340@robin.cs.nott.ac.uk> <7003@utzoo.UUCP>
Organization: McGill University, Montreal
Lines: 61
Keywords: stdio, buffering

> I try to use stdio as often as possible for several reasons [...] but
> I feel it lacks one or two calls [...]
> a) comment on these
> b) mention their own pet stdio hates
> c) show portable ways to implement these
> d) tell me they're already implemented ==> RTFM.

> Addition:	fpending(fp)
(Henry Spencer comments that "the right solution to that is fselect(),
not fpending().".  I disagree; suppose you want to select on a FILE*
and on a file descriptor both?  How do you tell the difference?

> Addition:	finvbuf(fp)
I wanted this one, so I wrote it.  But I called mine fdumpbuf().

> Addition:	fslam(fp)
Interesting.  Never wanted it, though.

> Addition:	fbufsiz(fp), fbuftype(fp)
Never wanted 'em.

> An inconsistency - why is there no ungetchar(c) defined??
I have wondered.

Here are the things I have wanted badly enough to add to stdio:

fdumpbuf(FILE *f)
	Mentioned above, throws away the in-core buffer.

FILE *fopenfxn(int (*fxn)(), char *mode)
	Function-stream I/O.  Returns a FILE*, open for read or write
	(not both, "r+" is treated as "r").  When a character is
	written to (resp. read from) the stream, the function is
	called.  On write, the character written is passed as an
	argument; on read, the returned value is returned to the user
	(or to scanf etc).

FILE *fopenstr(char *str, int len, char *mode)
	An extension to sprintf() and sscanf().  This returns a stream
	which performs I/O to a string (this makes sprintf() and
	sscanf() unnecessay, though they are still convenient).

unfdopen(FILE *f)
	Undoes fdopen(), that is, closes the FILE* without close()ing
	the underlying file descriptor.

Unfdopen is trivial; fopenfxn and fopenstr are implemented by making
the stream appear unbuffered to putc and getc and then changing _flsbuf
and _filbuf to add the functionality.

Comments anyone?
-- 
					der Mouse

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