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# sqrtl.m4 serial 11
dnl Copyright (C) 2010-2023 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
AC_DEFUN([gl_FUNC_SQRTL],
[
AC_REQUIRE([gl_MATH_H_DEFAULTS])
AC_REQUIRE([gl_LONG_DOUBLE_VS_DOUBLE])
dnl Persuade glibc <math.h> to declare sqrtl().
AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
SQRTL_LIBM=
AC_CACHE_CHECK([whether sqrtl() can be used without linking with libm],
[gl_cv_func_sqrtl_no_libm],
[
AC_LINK_IFELSE(
[AC_LANG_PROGRAM(
[[#ifndef __NO_MATH_INLINES
# define __NO_MATH_INLINES 1 /* for glibc */
#endif
#include <math.h>
long double (* volatile funcptr) (long double) = sqrtl;
long double x;]],
[[return funcptr (x) > 0.4
|| sqrtl (x) > 0.4;]])],
[gl_cv_func_sqrtl_no_libm=yes],
[gl_cv_func_sqrtl_no_libm=no])
])
if test $gl_cv_func_sqrtl_no_libm = no; then
AC_CACHE_CHECK([whether sqrtl() can be used with libm],
[gl_cv_func_sqrtl_in_libm],
[
save_LIBS="$LIBS"
LIBS="$LIBS -lm"
AC_LINK_IFELSE(
[AC_LANG_PROGRAM(
[[#ifndef __NO_MATH_INLINES
# define __NO_MATH_INLINES 1 /* for glibc */
#endif
#include <math.h>
long double (* volatile funcptr) (long double) = sqrtl;
long double x;]],
[[return funcptr (x) > 0.4
|| sqrtl (x) > 0.4;]])],
[gl_cv_func_sqrtl_in_libm=yes],
[gl_cv_func_sqrtl_in_libm=no])
LIBS="$save_LIBS"
])
if test $gl_cv_func_sqrtl_in_libm = yes; then
SQRTL_LIBM=-lm
fi
fi
if test $gl_cv_func_sqrtl_no_libm = yes \
|| test $gl_cv_func_sqrtl_in_libm = yes; then
dnl Also check whether it's declared.
dnl Mac OS X 10.3 has sqrtl() in libc but doesn't declare it in <math.h>.
AC_CHECK_DECL([sqrtl], , [HAVE_DECL_SQRTL=0], [[#include <math.h>]])
save_LIBS="$LIBS"
LIBS="$LIBS $SQRTL_LIBM"
gl_FUNC_SQRTL_WORKS
LIBS="$save_LIBS"
case "$gl_cv_func_sqrtl_works" in
*yes) ;;
*) REPLACE_SQRTL=1 ;;
esac
else
HAVE_DECL_SQRTL=0
HAVE_SQRTL=0
fi
if test $HAVE_SQRTL = 0 || test $REPLACE_SQRTL = 1; then
dnl Find libraries needed to link lib/sqrtl.c.
if test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 1; then
AC_REQUIRE([gl_FUNC_SQRT])
SQRTL_LIBM="$SQRT_LIBM"
else
AC_REQUIRE([gl_FUNC_ISNANL])
AC_REQUIRE([gl_FUNC_FREXPL])
AC_REQUIRE([gl_FUNC_LDEXPL])
AC_REQUIRE([gl_FUNC_SQRT])
dnl Append $ISNANL_LIBM to SQRTL_LIBM, avoiding gratuitous duplicates.
case " $SQRTL_LIBM " in
*" $ISNANL_LIBM "*) ;;
*) SQRTL_LIBM="$SQRTL_LIBM $ISNANL_LIBM" ;;
esac
dnl Append $FREXPL_LIBM to SQRTL_LIBM, avoiding gratuitous duplicates.
case " $SQRTL_LIBM " in
*" $FREXPL_LIBM "*) ;;
*) SQRTL_LIBM="$SQRTL_LIBM $FREXPL_LIBM" ;;
esac
dnl Append $LDEXPL_LIBM to SQRTL_LIBM, avoiding gratuitous duplicates.
case " $SQRTL_LIBM " in
*" $LDEXPL_LIBM "*) ;;
*) SQRTL_LIBM="$SQRTL_LIBM $LDEXPL_LIBM" ;;
esac
dnl Append $SQRT_LIBM to SQRTL_LIBM, avoiding gratuitous duplicates.
case " $SQRTL_LIBM " in
*" $SQRT_LIBM "*) ;;
*) SQRTL_LIBM="$SQRTL_LIBM $SQRT_LIBM" ;;
esac
fi
fi
AC_SUBST([SQRTL_LIBM])
])
dnl Test whether sqrtl() works.
dnl On OpenBSD 5.1/SPARC, sqrtl(8.1974099812331540680810141969554806865L) has
dnl rounding errors that eat up the last 8 to 9 decimal digits.
AC_DEFUN([gl_FUNC_SQRTL_WORKS],
[
AC_REQUIRE([AC_PROG_CC])
AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
AC_CACHE_CHECK([whether sqrtl works], [gl_cv_func_sqrtl_works],
[
AC_RUN_IFELSE(
[AC_LANG_SOURCE([[
#include <float.h>
#include <math.h>
#ifndef sqrtl /* for AIX */
extern
#ifdef __cplusplus
"C"
#endif
long double sqrtl (long double);
#endif
static long double
my_ldexpl (long double x, int d)
{
for (; d > 0; d--)
x *= 2.0L;
for (; d < 0; d++)
x *= 0.5L;
return x;
}
volatile long double x;
volatile long double y;
long double z;
int main ()
{
x = 8.1974099812331540680810141969554806865L;
y = sqrtl (x);
z = y * y - x;
z = my_ldexpl (z, LDBL_MANT_DIG);
if (z < 0)
z = - z;
if (z > 100.0L)
return 1;
return 0;
}
]])],
[gl_cv_func_sqrtl_works=yes],
[gl_cv_func_sqrtl_works=no],
[case "$host_os" in
openbsd*) gl_cv_func_sqrtl_works="guessing no" ;;
# Guess yes on native Windows.
mingw*) gl_cv_func_sqrtl_works="guessing yes" ;;
*) gl_cv_func_sqrtl_works="guessing yes" ;;
esac
])
])
])
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