xref: /csrg-svn/usr.bin/f77/libU77/isatty_.c (revision 23032)
14050Sdlw /*
2*23032Skre  * Copyright (c) 1980 Regents of the University of California.
3*23032Skre  * All rights reserved.  The Berkeley software License Agreement
4*23032Skre  * specifies the terms and conditions for redistribution.
54050Sdlw  *
6*23032Skre  *	@(#)isatty_.c	5.1	06/07/85
7*23032Skre  */
8*23032Skre 
9*23032Skre /*
104050Sdlw  * determine if stream is associated with a tty (async port)
114050Sdlw  *
124050Sdlw  * calling sequence:
134050Sdlw  *	logical	isatty, val
144050Sdlw  *	val = isatty (lunit)
154050Sdlw  * where:
164050Sdlw  *	val will be .TRUE. if lunit is associated with a 'tty'
174050Sdlw  */
184050Sdlw 
194050Sdlw #include	"../libI77/fiodefs.h"
204050Sdlw 
214050Sdlw extern unit units[];	/* logical units table from iolib */
224050Sdlw 
234050Sdlw long isatty_(u)
244050Sdlw long *u;
254050Sdlw {
264050Sdlw 	int	i;
274050Sdlw 	unit	*lu;
284050Sdlw 
294050Sdlw 	if (*u < 0 || *u >= MXUNIT)
304050Sdlw 		return(0);
314050Sdlw 	lu = &units[*u];
324050Sdlw 	if (!lu->ufd)
334050Sdlw 		return(0);
344050Sdlw 	return((long)(isatty(fileno(lu->ufd)) != 0));
354050Sdlw }
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