Path: utzoo!attcan!uunet!lll-winken!lll-tis!ames!haven!mimsy!chris
From: chris@mimsy.UUCP (Chris Torek)
Newsgroups: comp.lang.c
Subject: Re: Can ANYONE tell me why this code snippet doesn't work??
Keywords: varargs
Message-ID: <14093@mimsy.UUCP>
Date: 21 Oct 88 15:15:28 GMT
References: <7778@gryphon.CTS.COM> <315@uplog.se> <982@mina.liu.se> <316@uplog.se>
Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742
Lines: 62

>In article <982@mina.liu.se> mikpe@mina.liu.se (Mikael Pettersson) writes:
>>The great advantage in using varargs(3) is PORTABILITY. ...

In article <316@uplog.se> thomas@uplog.se (Thomas Hameenaho) writes:
>I agree fully with you. However not THAT many systems have v{sf}printf()
>(BSD systems doesn't, at least not 4.3) and my response was an attempt 
>to explain what was wrong with the code.

4.3BSD-tahoe does have v*printf.  Here they are.  Install in
src/lib/libc/stdio.  Note that vsprintf has the same bug that
sprintf has (it will scribble on a random fd if you print more
than 32767 characters).
---------------------------------vsprintf------------------------------
#include <stdio.h>
#include <varargs.h>

int
vsprintf(str, fmt, ap)
	char *str, *fmt;
	va_list ap;
{
	FILE f;
	int len;

	f._flag = _IOWRT+_IOSTRG;
	f._ptr = str;
	f._cnt = 32767;
	len = _doprnt(fmt, ap, &f);
	*f._ptr = 0;
	return (len);
}
---------------------------------vfprintf------------------------------
#include <stdio.h>
#include <varargs.h>

int
vfprintf(iop, fmt, ap)
	FILE *iop;
	char *fmt;
	va_list ap;
{
	int len;

	len = _doprnt(fmt, ap, &f);
	return (ferror(iop) ? EOF : len);
}
---------------------------------vprintf-------------------------------
#include <stdio.h>
#include <varargs.h>

int
vprintf(fmt, ap)
	char *fmt;
	va_list ap;
{
	int len;

	len = _doprnt(fmt, ap, stdout);
	return (ferror(stdout) ? EOF : len);
}
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163)
Domain:	chris@mimsy.umd.edu	Path:	uunet!mimsy!chris