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[metaconfig.git] / dist / U / d_castneg.U

?RCS: $Id: d_castneg.U 1 2006-08-24 12:32:52Z rmanfredi $
?RCS:
?RCS: Copyright (c) 1991-1997, 2004-2006, 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 4.0.
?RCS:
?RCS: $Log: d_castneg.U,v $
?RCS: Revision 3.0.1.2  1995/05/12  12:11:21  ram
?RCS: patch54: made sure cc and ccflags are conditional dependencies
?RCS: patch54: added improved test case for Interactive Unix
?RCS:
?RCS: Revision 3.0.1.1  1994/10/29  16:10:50  ram
?RCS: patch36: don't forget to tell user about compilation failures (ADO)
?RCS: patch36: declare signal handler correctly using 'signal_t' (ADO)
?RCS:
?RCS: Revision 3.0  1993/08/18  12:05:47  ram
?RCS: Baseline for dist 3.0 netwide release.
?RCS:
?X:
?X:	Can the compiler cast negative / odd floats to unsigned values.
?X:
?MAKE:d_castneg castflags: cat +cc +ccflags rm Setvar signal_t
?MAKE:	-pick add $@ %<
?S:d_castneg:
?S:	This variable conditionally defines CASTNEG, which indicates
?S:	wether the C compiler can cast negative float to unsigned.
?S:.
?S:castflags:
?S:	This variable contains a flag that precise difficulties the
?S:	compiler has casting odd floating values to unsigned long:
?S:		0 = ok
?S:		1 = couldn't cast < 0
?S:		2 = couldn't cast >= 0x80000000
?S:		4 = couldn't cast in argument expression list
?S:.
?C:CASTNEGFLOAT:
?C:	This symbol is defined if the C compiler can cast negative
?C:	numbers to unsigned longs, ints and shorts.
?C:.
?C:CASTFLAGS:
?C:	This symbol contains flags that say what difficulties the compiler
?C:	has casting odd floating values to unsigned long:
?C:		0 = ok
?C:		1 = couldn't cast < 0
?C:		2 = couldn't cast >= 0x80000000
?C:		4 = couldn't cast in argument expression list
?C:.
?H:#$d_castneg	CASTNEGFLOAT		/**/
?H:#define CASTFLAGS $castflags		/**/
?H:.
?F:!try
?LINT:set d_castneg
: check for ability to cast negative floats to unsigned
echo " "
echo 'Checking whether your C compiler can cast negative float to unsigned.' >&4
$cat >try.c <<EOCP
#include <sys/types.h>
#include <signal.h>
$signal_t blech() { exit(7); }
$signal_t blech_in_list() { exit(4); }
unsigned long dummy_long(p) unsigned long p; { return p; }
unsigned int dummy_int(p) unsigned int p; { return p; }
unsigned short dummy_short(p) unsigned short p; { return p; }
int main()
{
	double f = -123.;
	unsigned long along;
	unsigned int aint;
	unsigned short ashort;
	int result = 0;

	signal(SIGFPE, blech);
	along = (unsigned long)f;
	aint = (unsigned int)f;
	ashort = (unsigned short)f;
	if (along != (unsigned long)-123)
		result |= 1;
	if (aint != (unsigned int)-123)
		result |= 1;
	if (ashort != (unsigned short)-123)
		result |= 1;
	f = (double)0x40000000;
	f = f + f;
	along = 0;
	along = (unsigned long)f;
	if (along != 0x80000000)
		result |= 2;
	f -= 1.;
	along = 0;
	along = (unsigned long)f;
	if (along != 0x7fffffff)
		result |= 1;
	f += 2.;
	along = 0;
	along = (unsigned long)f;
	if (along != 0x80000001)
		result |= 2;
	if (result)
		exit(result);
?X:
?X: The following is a test for Interactive Unix Version 4.1, which
?X: has an 'improved' compiler which can correctly cast negative
?X: floats in expression lists, but apparently not in argument lists.
?X:	Contributed by Winfried Koenig <win@incom.rhein-main.de>
?X:
	signal(SIGFPE, blech_in_list);
	f = 123.;
	along = dummy_long((unsigned long)f);
	aint = dummy_int((unsigned int)f);
	ashort = dummy_short((unsigned short)f);
	if (along != (unsigned long)123)
		result |= 4;
	if (aint != (unsigned int)123)
		result |= 4;
	if (ashort != (unsigned short)123)
		result |= 4;
	exit(result);

}
EOCP
if $cc $ccflags -o try try.c >/dev/null 2>&1; then
	./try
	castflags=$?
else
	echo "(I can't seem to compile the test program--assuming it can't)"
	castflags=7
fi
case "$castflags" in
0)	val="$define"
	echo "Yup, it can."
	;;
*)	val="$undef"
	echo "Nope, it can't."
	;;
esac
set d_castneg
eval $setvar
$rm -f try.*