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?RCS: $Id: d_castneg.U 167 2013-05-08 17:58:00Z rmanfredi $
?RCS:
?RCS: Copyright (c) 1991-1997, 2004-2006, Raphael Manfredi
?RCS:
?RCS: You may redistribute only under the terms of the Artistic License,
?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 License; 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.*
|
