?RCS: $Id: voidflags.U,v 3.0.1.2 1997/02/28 16:27:58 ram Exp $
?RCS:
?RCS: Copyright (c) 1991-1993, Raphael Manfredi
?RCS:
?RCS: You may redistribute only under the terms of the Artistic Licence,
?RCS: as specified in the README file that comes with the distribution.
?RCS: You may reuse parts of this distribution only within the terms of
?RCS: that same Artistic Licence; a copy of which may be found at the root
?RCS: of the source tree for dist 3.0.
?RCS:
?RCS: $Log: voidflags.U,v $
?RCS: Revision 3.0.1.2  1997/02/28  16:27:58  ram
?RCS: patch61: don't prompt them if the void support is high enough for us
?RCS:
?RCS: Revision 3.0.1.1  1995/01/11  15:37:44  ram
?RCS: patch45: cosmetic change to avoid spurious blank lines when using -s
?RCS:
?RCS: Revision 3.0  1993/08/18  12:10:01  ram
?RCS: Baseline for dist 3.0 netwide release.
?RCS:
?MAKE:voidflags defvoidused: cat rm_try contains +cc +ccflags package \
	Oldconfig Myread i_stdlib
?MAKE:	-pick add $@ %<
?S:voidflags:
?S:	This variable contains the eventual value of the VOIDFLAGS symbol,
?S:	which indicates how much support of the void type is given by this
?S:	compiler.  See VOIDFLAGS for more info.
?S:.
?S:defvoidused:
?S:	This variable contains the default value of the VOIDUSED symbol (15).
?S:.
?X:	Exceptionally, we have to explicitely alias the symbol name for
?X: config_h.SH, otherwise the comment would not appear.
?C:VOIDFLAGS ~ %<:
?C:	This symbol indicates how much support of the void type is given by this
?C:	compiler.  What various bits mean:
?C:
?C:	    1 = supports declaration of void
?C:	    2 = supports arrays of pointers to functions returning void
?C:	    4 = supports comparisons between pointers to void functions and
?C:		    addresses of void functions
?C:	    8 = suports declaration of generic void pointers
?C:
?C:	The package designer should define VOIDUSED to indicate the requirements
?C:	of the package.  This can be done either by #defining VOIDUSED before
?C:	including config.h, or by defining defvoidused in Myinit.U.  If the
?C:	latter approach is taken, only those flags will be tested.  If the
?C:	level of void support necessary is not present, defines void to int.
?C:.
?H:?%<:#ifndef VOIDUSED
?H:?%<:#define VOIDUSED $defvoidused
?H:?%<:#endif
?H:?%<:#define VOIDFLAGS $voidflags
?H:?%<:#if (VOIDFLAGS & VOIDUSED) != VOIDUSED
?H:?%<:#define void int		/* is void to be avoided? */
?H:?%<:#define M_VOID			/* Xenix strikes again */
?H:?%<:#endif
?H:.
?W:%<:void
?INIT:: full support for void wanted by default
?INIT:defvoidused=15
?INIT:
?LINT:known void M_VOID VOIDUSED
: check for void type
echo " "
echo "Checking to see how well your C compiler groks the void type..." >&4
case "$voidflags" in
'')
	$cat >try.c <<EOCP
#$i_stdlib I_STDLIB
#ifdef I_STDLIB
#include <stdlib.h>
#endif
#if TRY & 1
void sub() {
#else
sub() {
#endif
	extern void moo();	/* function returning void */
	void (*goo)();		/* ptr to func returning void */
#if TRY & 8
	void *hue;		/* generic ptr */
#endif
#if TRY & 2
	void (*foo[10])();
#endif

#if TRY & 4
	if(goo == moo) {
		exit(0);
	}
#endif
	exit(0);
}
int main() { sub(); }
EOCP
?X: This unit used to use cc -S in those tests to try to speed up things, but
?X: unfortunately, AIX 3.2 does not support this option.
	if $cc $ccflags -c -DTRY=$defvoidused try.c >.out 2>&1 ; then
		voidflags=$defvoidused
	echo "Good.  It appears to support void to the level $package wants.">&4
		if $contains warning .out >/dev/null 2>&1; then
			echo "However, you might get some warnings that look like this:"
			$cat .out
		fi
	else
echo "Hmm, your compiler has some difficulty with void. Checking further..." >&4
		if $cc $ccflags -c -DTRY=1 try.c >/dev/null 2>&1; then
			echo "It supports 1..."
			if $cc $ccflags -c -DTRY=3 try.c >/dev/null 2>&1; then
				echo "It also supports 2..."
				if $cc $ccflags -c -DTRY=7 try.c >/dev/null 2>&1; then
					voidflags=7
					echo "And it supports 4 but not 8 definitely."
				else
					echo "It doesn't support 4..."
					if $cc $ccflags -c -DTRY=11 try.c >/dev/null 2>&1; then
						voidflags=11
						echo "But it supports 8."
					else
						voidflags=3
						echo "Neither does it support 8."
					fi
				fi
			else
				echo "It does not support 2..."
				if $cc $ccflags -c -DTRY=13 try.c >/dev/null 2>&1; then
					voidflags=13
					echo "But it supports 4 and 8."
				else
					if $cc $ccflags -c -DTRY=5 try.c >/dev/null 2>&1; then
						voidflags=5
						echo "And it supports 4 but has not heard about 8."
					else
						echo "However it supports 8 but not 4."
					fi
				fi
			fi
		else
			echo "There is no support at all for void."
			voidflags=0
		fi
	fi
esac
?X: Only prompt user if support does not match the level we want
case "$voidflags" in
"$defvoidused") ;;
*)	$cat >&4 <<'EOM'
  Support flag bits are:
    1: basic void declarations.
    2: arrays of pointers to functions returning void.
    4: operations between pointers to and addresses of void functions.
    8: generic void pointers.
EOM
	dflt="$voidflags";
	rp="Your void support flags add up to what?"
	. ./myread
	voidflags="$ans"
	;;
esac
$rm_try