Another printf-type question

[gwyn at brl-smoke.UUCP]

In article <2138 at brl-smoke.ARPA> LINNDR%VUENGVAX.BITNET at WISCVM.ARPA writes:
>invprintf(fmt,args)
>{
>        printf(<string to go into inverse video mode>);
>        printf(fmt,args);
>        printf(<string to leave inverse mode>);
>}
>
>This simple solution didn't work. Oh great gurus of such things, what
>should I have done?

Assuming you're using UNIX System V Release 2.0 for sake of concreteness,

#include	<stdio.h>
#include	<varargs.h>

void
invprintf( va_alist )
	va_dcl
	{
	char	*fmt;			/* printf control string */
	va_list	args;			/* argument pointer */

	(void)fputs( "string to enter inverse video mode", stdout );

	va_start( args );

	fmt = va_arg( args, char * );

	(void)vprintf( fmt, args );	/* warning! not printf(va_arg etc. */

	va_end( args );

	(void)fputs( "string to leave inverse video mode", stdout );
	}

The final mechanism of ANSI X3J11 will probably be slightly different.

P.S.  You should perhaps also test whether the write to the terminal succeeds.