2 dnl Copyright (C) 2012 Free Software Foundation, Inc.
3 dnl This file is free software; the Free Software Foundation
4 dnl gives unlimited permission to copy and/or distribute it,
5 dnl with or without modifications, as long as this notice is preserved.
7 AC_DEFUN([gl_FUNC_HYPOT],
9 m4_divert_text([DEFAULTS], [gl_hypot_required=plain])
10 AC_REQUIRE([gl_MATH_H_DEFAULTS])
12 dnl Persuade glibc <math.h> to declare hypot().
13 AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
15 dnl Determine HYPOT_LIBM.
16 gl_COMMON_DOUBLE_MATHFUNC([hypot])
18 m4_ifdef([gl_FUNC_HYPOT_IEEE], [
19 if test $gl_hypot_required = ieee && test $REPLACE_HYPOT = 0; then
20 AC_CACHE_CHECK([whether hypot works according to ISO C 99 with IEC 60559],
21 [gl_cv_func_hypot_ieee],
24 LIBS="$LIBS $HYPOT_LIBM"
27 #ifndef __NO_MATH_INLINES
28 # define __NO_MATH_INLINES 1 /* for glibc */
31 /* Compare two numbers with ==.
32 This is a separate function because IRIX 6.5 "cc -O" miscompiles an
35 numeric_equal (double x, double y)
39 static double dummy (double x, double y) { return 0; }
42 int main (int argc, char *argv[])
44 double (*my_hypot) (double, double) = argc ? hypot : dummy;
46 /* Test hypot(NaN,Infinity).
47 This test fails on OSF/1 5.1 and native Windows. */
48 f = my_hypot (zero / zero, one / zero);
49 if (!numeric_equal (f, f))
54 [gl_cv_func_hypot_ieee=yes],
55 [gl_cv_func_hypot_ieee=no],
56 [gl_cv_func_hypot_ieee="guessing no"])
59 case "$gl_cv_func_hypot_ieee" in
65 if test $REPLACE_HYPOT = 1; then
66 dnl Find libraries needed to link lib/hypot.c.
67 AC_REQUIRE([gl_FUNC_FABS])
68 AC_REQUIRE([gl_FUNC_FREXP])
69 AC_REQUIRE([gl_FUNC_LDEXP])
70 AC_REQUIRE([gl_FUNC_SQRT])
72 dnl Append $FABS_LIBM to HYPOT_LIBM, avoiding gratuitous duplicates.
73 case " $HYPOT_LIBM " in
75 *) HYPOT_LIBM="$HYPOT_LIBM $FABS_LIBM" ;;
77 dnl Append $FREXP_LIBM to HYPOT_LIBM, avoiding gratuitous duplicates.
78 case " $HYPOT_LIBM " in
80 *) HYPOT_LIBM="$HYPOT_LIBM $FREXP_LIBM" ;;
82 dnl Append $LDEXP_LIBM to HYPOT_LIBM, avoiding gratuitous duplicates.
83 case " $HYPOT_LIBM " in
85 *) HYPOT_LIBM="$HYPOT_LIBM $LDEXP_LIBM" ;;
87 dnl Append $SQRT_LIBM to HYPOT_LIBM, avoiding gratuitous duplicates.
88 case " $HYPOT_LIBM " in
90 *) HYPOT_LIBM="$HYPOT_LIBM $SQRT_LIBM" ;;