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# roundf.m4 serial 17
dnl Copyright (C) 2007-2016 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_ROUNDF],
[
m4_divert_text([DEFAULTS], [gl_roundf_required=plain])
AC_REQUIRE([gl_MATH_H_DEFAULTS])
dnl Persuade glibc <math.h> to declare roundf().
AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
gl_CHECK_MATH_LIB([ROUNDF_LIBM], [x = roundf (x);],
[extern
#ifdef __cplusplus
"C"
#endif
float roundf (float);
])
if test "$ROUNDF_LIBM" != missing; then
HAVE_ROUNDF=1
dnl Also check whether it's declared.
dnl IRIX 6.5 has roundf() in libm but doesn't declare it in <math.h>.
AC_CHECK_DECLS([roundf], , [HAVE_DECL_ROUNDF=0], [[#include <math.h>]])
dnl Test whether roundf() produces correct results. On mingw, for
dnl x = 1/2 - 2^-25, the system's roundf() returns a wrong result.
AC_REQUIRE([AC_PROG_CC])
AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
AC_CACHE_CHECK([whether roundf works], [gl_cv_func_roundf_works],
[
save_LIBS="$LIBS"
LIBS="$LIBS $ROUNDF_LIBM"
AC_RUN_IFELSE([AC_LANG_SOURCE([[
#include <float.h>
#include <math.h>
extern
#ifdef __cplusplus
"C"
#endif
float roundf (float);
#ifdef _MSC_VER
# pragma fenv_access (off)
#endif
int main()
{
/* 2^FLT_MANT_DIG. */
static const float TWO_MANT_DIG =
/* Assume FLT_MANT_DIG <= 3 * 31.
Use the identity n = floor(n/3) + floor((n+1)/3) + floor((n+2)/3). */
(float) (1U << (FLT_MANT_DIG / 3))
* (float) (1U << ((FLT_MANT_DIG + 1) / 3))
* (float) (1U << ((FLT_MANT_DIG + 2) / 3));
volatile float x = 0.5f - 0.5f / TWO_MANT_DIG;
exit (x < 0.5f && roundf (x) != 0.0f);
}]])], [gl_cv_func_roundf_works=yes], [gl_cv_func_roundf_works=no],
[case "$host_os" in
mingw*) gl_cv_func_roundf_works="guessing no";;
*) gl_cv_func_roundf_works="guessing yes";;
esac
])
LIBS="$save_LIBS"
])
case "$gl_cv_func_roundf_works" in
*no) REPLACE_ROUNDF=1 ;;
esac
m4_ifdef([gl_FUNC_ROUNDF_IEEE], [
if test $gl_roundf_required = ieee && test $REPLACE_ROUNDF = 0; then
AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
AC_CACHE_CHECK([whether roundf works according to ISO C 99 with IEC 60559],
[gl_cv_func_roundf_ieee],
[
save_LIBS="$LIBS"
LIBS="$LIBS $ROUNDF_LIBM"
AC_RUN_IFELSE(
[AC_LANG_SOURCE([[
#ifndef __NO_MATH_INLINES
# define __NO_MATH_INLINES 1 /* for glibc */
#endif
#include <math.h>
extern
#ifdef __cplusplus
"C"
#endif
float roundf (float);
]gl_FLOAT_MINUS_ZERO_CODE[
]gl_FLOAT_SIGNBIT_CODE[
static float dummy (float f) { return 0; }
int main (int argc, char *argv[])
{
float (*my_roundf) (float) = argc ? roundf : dummy;
int result = 0;
/* Test whether roundf (-0.0f) is -0.0f. */
if (signbitf (minus_zerof) && !signbitf (my_roundf (minus_zerof)))
result |= 1;
/* Test whether roundf (-0.3f) is -0.0f. */
if (signbitf (-0.3f) && !signbitf (my_roundf (-0.3f)))
result |= 2;
return result;
}
]])],
[gl_cv_func_roundf_ieee=yes],
[gl_cv_func_roundf_ieee=no],
[case "$host_os" in
# Guess yes on glibc systems.
*-gnu*) gl_cv_func_roundf_ieee="guessing yes" ;;
# If we don't know, assume the worst.
*) gl_cv_func_roundf_ieee="guessing no" ;;
esac
])
LIBS="$save_LIBS"
])
case "$gl_cv_func_roundf_ieee" in
*yes) ;;
*) REPLACE_ROUNDF=1 ;;
esac
fi
])
else
HAVE_ROUNDF=0
HAVE_DECL_ROUNDF=0
fi
if test $HAVE_ROUNDF = 0 || test $REPLACE_ROUNDF = 1; then
dnl Find libraries needed to link lib/roundf.c.
AC_CHECK_DECLS([ceilf, floorf], , , [[#include <math.h>]])
if test "$ac_cv_have_decl_floorf" = yes \
&& test "$ac_cv_have_decl_ceilf" = yes; then
gl_FUNC_FLOORF_LIBS
gl_FUNC_CEILF_LIBS
if test "$FLOORF_LIBM" != '?' && test "$CEILF_LIBM" != '?'; then
AC_DEFINE([HAVE_FLOORF_AND_CEILF], [1],
[Define if the both the floorf() and ceilf() functions exist.])
ROUNDF_LIBM=
dnl Append $FLOORF_LIBM to ROUNDF_LIBM, avoiding gratuitous duplicates.
case " $ROUNDF_LIBM " in
*" $FLOORF_LIBM "*) ;;
*) ROUNDF_LIBM="$ROUNDF_LIBM $FLOORF_LIBM" ;;
esac
dnl Append $CEILF_LIBM to ROUNDF_LIBM, avoiding gratuitous duplicates.
case " $ROUNDF_LIBM " in
*" $CEILF_LIBM "*) ;;
*) ROUNDF_LIBM="$ROUNDF_LIBM $CEILF_LIBM" ;;
esac
else
ROUNDF_LIBM=
fi
else
ROUNDF_LIBM=
fi
fi
AC_SUBST([ROUNDF_LIBM])
])
|
