?RCS: $Id$
?RCS:
?RCS: Copyright (c) 2000 Jarkko Hietaniemi
?RCS:
?RCS: You may distribute under the terms of either the GNU General Public
?RCS: License or the Artistic License, as specified in the README file.
?RCS:
?MAKE:d_modfl d_modflproto d_modfl_pow32_bug: Inlibc Compile Hasproto cat \
	rm_try test sPRIfldbl d_longdbl osname gccversion ccflags run \
	uselongdouble i_math \
	d_sqrtl d_aintl d_copysignl d_ilogbl d_scalbnl d_frexpl
?MAKE:	-pick add $@ %<
?S:d_modfl:
?S:	This variable conditionally defines the HAS_MODFL symbol, which
?S:	indicates to the C program that the modfl() routine is available.
?S:.
?S:d_modflproto:
?S:	This symbol, if defined, indicates that the system provides
?S:	a prototype for the modfl() function.  Otherwise, it is up
?S:	to the program to supply one.  C99 says it should be
?S:		long double modfl(long double, long double *);
?S:.
?S:d_modfl_pow32_bug:
?S:	This variable conditionally defines the HAS_MODFL_POW32_BUG symbol,
?S:	which indicates that modfl() is broken for long doubles >= pow(2, 32).
?S:	For example from 4294967303.150000 one would get 4294967302.000000
?S:	and 1.150000.  The bug has been seen in certain versions of glibc,
?S:	release 2.2.2 is known to be okay.
?S:.
?C:HAS_MODFL:
?C:	This symbol, if defined, indicates that the modfl routine is
?C:	available to split a long double x into a fractional part f and
?C:	an integer part i such that |f| < 1.0 and (f + i) = x.
?C:.
?C:HAS_MODFL_PROTO:
?C:	This symbol, if defined, indicates that the system provides
?C:	a prototype for the modfl() function.  Otherwise, it is up
?C:	to the program to supply one.
?C:.
?C:HAS_MODFL_POW32_BUG:
?C:	This symbol, if defined, indicates that the modfl routine is
?C:	broken for long doubles >= pow(2, 32).
?C:	For example from 4294967303.150000 one would get 4294967302.000000
?C:	and 1.150000.  The bug has been seen in certain versions of glibc,
?C:	release 2.2.2 is known to be okay.
?C:.
?H:#$d_modfl HAS_MODFL		/**/
?H:#$d_modflproto HAS_MODFL_PROTO		/**/
?H:#$d_modfl_pow32_bug HAS_MODFL_POW32_BUG		/**/
?H:.
?T:foo saveccflags message
?F:!try
?LINT:set d_modflproto
?LINT:change ccflags
: see if modfl exists
set modfl d_modfl
eval $inlibc

: see if prototype for modfl is available
echo " "
set d_modflproto modfl $i_math math.h
eval $hasproto

d_modfl_pow32_bug="$undef"

case "$d_longdbl$d_modfl" in
$define$define)
	$cat <<EOM
Checking to see whether your modfl() is okay for large values...
EOM
$cat >try.c <<EOCP
#include <math.h>
#include <stdio.h>
EOCP
if $test "X$d_modflproto" != "X$define"; then
	$cat >>try.c <<EOCP
/* Sigh. many current glibcs provide the function, but do not prototype it. */
long double modfl (long double, long double *);
EOCP
fi
$cat >>try.c <<EOCP
int main() {
    long double nv = 4294967303.15;
    long double v, w;
    v = modfl(nv, &w);
#ifdef __GLIBC__
    printf("glibc");
#endif
    printf(" %"$sPRIfldbl" %"$sPRIfldbl" %"$sPRIfldbl"\n", nv, v, w);
    return 0;
}
EOCP
	case "$osname:$gccversion" in
	aix:)	saveccflags="$ccflags"
		ccflags="$ccflags -qlongdouble" ;; # to avoid core dump
	esac
	set try
	if eval $compile; then
		foo=`$run ./try`
		case "$foo" in
		*" 4294967303.150000 1.150000 4294967302.000000")
			echo >&4 "Your modfl() is broken for large values."
			d_modfl_pow32_bug="$define"
			case "$foo" in
			glibc)	echo >&4 "You should upgrade your glibc to at least 2.2.2 to get a fixed modfl()."
			;;
			esac
			;;
		*" 4294967303.150000 0.150000 4294967303.000000")
			echo >&4 "Your modfl() seems okay for large values."
			;;
		*)	echo >&4 "I don't understand your modfl() at all."
			d_modfl="$undef"
			;;
		esac
		$rm_try
	else
		echo "I cannot figure out whether your modfl() is okay, assuming it isn't."
		d_modfl="$undef"
	fi
	case "$osname:$gccversion" in
	aix:)	ccflags="$saveccflags" ;; # restore
	esac
	;;
esac

if $test "$uselongdouble" = "$define"; then
    message=""
    if $test "$d_sqrtl" != "$define"; then
	message="$message sqrtl"
    fi
    if $test "$d_modfl" != "$define"; then
	if $test "$d_aintl:$d_copysignl" = "$define:$define"; then
	    echo "You have both aintl and copysignl, so I can emulate modfl."
	else
	    message="$message modfl"
	fi
    fi
    if $test "$d_frexpl" != "$define"; then
	if $test "$d_ilogbl:$d_scalbnl" = "$define:$define"; then
	    echo "You have both ilogbl and scalbnl, so I can emulate frexpl."
	else
	    message="$message frexpl"
	fi
    fi

    if $test "$message" != ""; then
	$cat <<EOM >&4

*** You requested the use of long doubles but you do not seem to have
*** the following mathematical functions needed for long double support:
***    $message
*** Please rerun Configure without -Duselongdouble and/or -Dusemorebits.
*** Cannot continue, aborting.

EOM

	exit 1
    fi
fi