Path: utzoo!mnetor!uunet!vsi!friedl
From: friedl@vsi.UUCP (Stephen J. Friedl)
Newsgroups: comp.lang.c
Subject: Re: variable number of arguments
Message-ID: <51@vsi.UUCP>
Date: 26 Feb 88 05:22:57 GMT
References: <1608@byzantium.UUCP> <1632@mhres.mh.nl>
Organization: V-Systems, Inc. -- Santa Ana, CA
Lines: 50
Keywords: arguments, varargs
Summary: suggested fix to the example

In article <1632@mhres.mh.nl>, hst@mhres.mh.nl (Klaas Hemstra) writes:
> Try using the vsprintf() function together with varargs.
> Example:
> 
>    MyXText( X, Y, formatString, va_alist)
>    ....
>    va_dcl
>    {   char 	TempString[100];
>        va_list 	args;
>        
>        va_start(args);
>        vsprintf(TempString , formatString, args);
> 
>        va_end(args);
> 
>    }

     I think you are better with:

	MyXText(va_alist)
	va_dcl
	{
	char	buf[256];	/* buffer to format to	*/
	int	x, y;		/* X/Y location		*/
	char	*fmt;		/* printf format string	*/
	va_args	args;

		va_start(args);

		x   = va_arg(args, int);	/* GET...	*/
		y   = va_arg(args, int);	/* .. ALL...	*/
		fmt = va_arg(args, char *);	/* .... ARGS..	*/

		vsprintf(buf, fmt, args);

		va_end(args);
	}

     I have no specific reason to doubt the portability, but it
strikes me that since args are so crazy on various machines (stack
grows up, stack grows down, params passed in registers, etc.)
that letting varargs handle *all* the details would not be a bad
idea.

     Just a thought,
     Steve
-- 
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