diff options
Diffstat (limited to '')
| -rw-r--r-- | m4/frexp.m4 | 181 |
1 files changed, 181 insertions, 0 deletions
diff --git a/m4/frexp.m4 b/m4/frexp.m4 new file mode 100644 index 0000000..5d977d4 --- /dev/null +++ b/m4/frexp.m4 @@ -0,0 +1,181 @@ +# frexp.m4 serial 16 +dnl Copyright (C) 2007-2020 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*) gl_cv_func_frexp_works="guessing no" ;; + mingw*) # Guess yes with MSVC, no with mingw. + AC_EGREP_CPP([Good], [ +#ifdef _MSC_VER + Good +#endif + ], + [gl_cv_func_frexp_works="guessing yes"], + [gl_cv_func_frexp_works="guessing no"]) + ;; + *) gl_cv_func_frexp_works="guessing yes" ;; + esac + ]) + ]) +]) |