| # frexp.m4 serial 15 |
| 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_FREXP], |
| [ |
| AC_REQUIRE([gl_MATH_H_DEFAULTS]) |
| AC_REQUIRE([gl_CHECK_FREXP_NO_LIBM]) |
| FREXP_LIBM= |
| if test $gl_cv_func_frexp_no_libm = no; then |
| AC_CACHE_CHECK([whether frexp() can be used with libm], |
| [gl_cv_func_frexp_in_libm], |
| [ |
| save_LIBS="$LIBS" |
| LIBS="$LIBS -lm" |
| AC_LINK_IFELSE( |
| [AC_LANG_PROGRAM( |
| [[#include <math.h> |
| double x;]], |
| [[int e; return frexp (x, &e) > 0;]])], |
| [gl_cv_func_frexp_in_libm=yes], |
| [gl_cv_func_frexp_in_libm=no]) |
| LIBS="$save_LIBS" |
| ]) |
| if test $gl_cv_func_frexp_in_libm = yes; then |
| FREXP_LIBM=-lm |
| fi |
| fi |
| if test $gl_cv_func_frexp_no_libm = yes \ |
| || test $gl_cv_func_frexp_in_libm = yes; then |
| save_LIBS="$LIBS" |
| LIBS="$LIBS $FREXP_LIBM" |
| gl_FUNC_FREXP_WORKS |
| LIBS="$save_LIBS" |
| case "$gl_cv_func_frexp_works" in |
| *yes) gl_func_frexp=yes ;; |
| *) gl_func_frexp=no; REPLACE_FREXP=1; FREXP_LIBM= ;; |
| esac |
| else |
| gl_func_frexp=no |
| fi |
| if test $gl_func_frexp = yes; then |
| AC_DEFINE([HAVE_FREXP], [1], |
| [Define if the frexp() function is available and works.]) |
| fi |
| AC_SUBST([FREXP_LIBM]) |
| ]) |
| |
| AC_DEFUN([gl_FUNC_FREXP_NO_LIBM], |
| [ |
| AC_REQUIRE([gl_MATH_H_DEFAULTS]) |
| AC_REQUIRE([gl_CHECK_FREXP_NO_LIBM]) |
| if test $gl_cv_func_frexp_no_libm = yes; then |
| gl_FUNC_FREXP_WORKS |
| case "$gl_cv_func_frexp_works" in |
| *yes) gl_func_frexp_no_libm=yes ;; |
| *) gl_func_frexp_no_libm=no; REPLACE_FREXP=1 ;; |
| esac |
| else |
| gl_func_frexp_no_libm=no |
| dnl Set REPLACE_FREXP here because the system may have frexp in libm. |
| REPLACE_FREXP=1 |
| fi |
| if test $gl_func_frexp_no_libm = yes; then |
| AC_DEFINE([HAVE_FREXP_IN_LIBC], [1], |
| [Define if the frexp() function is available in libc.]) |
| fi |
| ]) |
| |
| dnl Test whether frexp() can be used without linking with libm. |
| dnl Set gl_cv_func_frexp_no_libm to 'yes' or 'no' accordingly. |
| AC_DEFUN([gl_CHECK_FREXP_NO_LIBM], |
| [ |
| AC_CACHE_CHECK([whether frexp() can be used without linking with libm], |
| [gl_cv_func_frexp_no_libm], |
| [ |
| AC_LINK_IFELSE( |
| [AC_LANG_PROGRAM( |
| [[#include <math.h> |
| double x;]], |
| [[int e; return frexp (x, &e) > 0;]])], |
| [gl_cv_func_frexp_no_libm=yes], |
| [gl_cv_func_frexp_no_libm=no]) |
| ]) |
| ]) |
| |
| dnl Test whether frexp() works also on denormalized numbers (this fails e.g. on |
| dnl NetBSD 3.0), on infinite numbers (this fails e.g. on IRIX 6.5 and mingw), |
| dnl and on negative zero (this fails e.g. on NetBSD 4.99 and mingw). |
| AC_DEFUN([gl_FUNC_FREXP_WORKS], |
| [ |
| AC_REQUIRE([AC_PROG_CC]) |
| AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles |
| AC_CHECK_DECLS_ONCE([alarm]) |
| AC_CACHE_CHECK([whether frexp works], [gl_cv_func_frexp_works], |
| [ |
| AC_RUN_IFELSE( |
| [AC_LANG_SOURCE([[ |
| #include <float.h> |
| #include <math.h> |
| #include <string.h> |
| #if HAVE_DECL_ALARM |
| # include <signal.h> |
| # include <unistd.h> |
| #endif |
| /* HP cc on HP-UX 10.20 has a bug with the constant expression -0.0. |
| ICC 10.0 has a bug when optimizing the expression -zero. |
| The expression -DBL_MIN * DBL_MIN does not work when cross-compiling |
| to PowerPC on Mac OS X 10.5. */ |
| #if defined __hpux || defined __sgi || defined __ICC |
| static double |
| compute_minus_zero (void) |
| { |
| return -DBL_MIN * DBL_MIN; |
| } |
| # define minus_zero compute_minus_zero () |
| #else |
| double minus_zero = -0.0; |
| #endif |
| int main() |
| { |
| int result = 0; |
| int i; |
| volatile double x; |
| double zero = 0.0; |
| #if HAVE_DECL_ALARM |
| /* NeXTstep 3.3 frexp() runs into an endless loop when called on an infinite |
| number. Let the test fail in this case. */ |
| signal (SIGALRM, SIG_DFL); |
| alarm (5); |
| #endif |
| /* Test on denormalized numbers. */ |
| for (i = 1, x = 1.0; i >= DBL_MIN_EXP; i--, x *= 0.5) |
| ; |
| if (x > 0.0) |
| { |
| int exp; |
| double y = frexp (x, &exp); |
| /* On machines with IEEE754 arithmetic: x = 1.11254e-308, exp = -1022. |
| On NetBSD: y = 0.75. Correct: y = 0.5. */ |
| if (y != 0.5) |
| result |= 1; |
| } |
| /* Test on infinite numbers. */ |
| x = 1.0 / zero; |
| { |
| int exp; |
| double y = frexp (x, &exp); |
| if (y != x) |
| result |= 2; |
| } |
| /* Test on negative zero. */ |
| x = minus_zero; |
| { |
| int exp; |
| double y = frexp (x, &exp); |
| if (memcmp (&y, &x, sizeof x)) |
| result |= 4; |
| } |
| return result; |
| }]])], |
| [gl_cv_func_frexp_works=yes], |
| [gl_cv_func_frexp_works=no], |
| [case "$host_os" in |
| netbsd* | irix* | mingw*) gl_cv_func_frexp_works="guessing no";; |
| *) gl_cv_func_frexp_works="guessing yes";; |
| esac |
| ]) |
| ]) |
| ]) |