1 files changed, 233 insertions, 0 deletions
diff --git a/m4/frexpl.m4 b/m4/frexpl.m4
new file mode 100644
index 0000000..eb79aea
--- /dev/null
+++ b/m4/frexpl.m4
@@ -0,0 +1,233 @@
+# frexpl.m4 serial 23
+dnl Copyright (C) 2007-2023 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_FREXPL],
+[
+  AC_REQUIRE([gl_MATH_H_DEFAULTS])
+  AC_REQUIRE([gl_LONG_DOUBLE_VS_DOUBLE])
+
+  dnl Persuade glibc <math.h> to declare frexpl().
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+
+  dnl Check whether it's declared.
+  dnl Mac OS X 10.3 has frexpl() in libc but doesn't declare it in <math.h>.
+  AC_CHECK_DECL([frexpl], , [HAVE_DECL_FREXPL=0], [[#include <math.h>]])
+
+  FREXPL_LIBM=
+  if test $HAVE_DECL_FREXPL = 1; then
+    gl_CHECK_FREXPL_NO_LIBM
+    if test $gl_cv_func_frexpl_no_libm = no; then
+      AC_CACHE_CHECK([whether frexpl() can be used with libm],
+        [gl_cv_func_frexpl_in_libm],
+        [
+          save_LIBS="$LIBS"
+          LIBS="$LIBS -lm"
+          AC_LINK_IFELSE(
+            [AC_LANG_PROGRAM(
+               [[#include <math.h>
+                 long double x;]],
+               [[int e; return frexpl (x, &e) > 0;]])],
+            [gl_cv_func_frexpl_in_libm=yes],
+            [gl_cv_func_frexpl_in_libm=no])
+          LIBS="$save_LIBS"
+        ])
+      if test $gl_cv_func_frexpl_in_libm = yes; then
+        FREXPL_LIBM=-lm
+      fi
+    fi
+    if test $gl_cv_func_frexpl_no_libm = yes \
+       || test $gl_cv_func_frexpl_in_libm = yes; then
+      save_LIBS="$LIBS"
+      LIBS="$LIBS $FREXPL_LIBM"
+      gl_FUNC_FREXPL_WORKS
+      LIBS="$save_LIBS"
+      case "$gl_cv_func_frexpl_works" in
+        *yes) gl_func_frexpl=yes ;;
+        *)    gl_func_frexpl=no; REPLACE_FREXPL=1 ;;
+      esac
+    else
+      gl_func_frexpl=no
+    fi
+    if test $gl_func_frexpl = yes; then
+      AC_DEFINE([HAVE_FREXPL], [1],
+        [Define if the frexpl() function is available.])
+    fi
+  fi
+  if test $HAVE_DECL_FREXPL = 0 || test $gl_func_frexpl = no; then
+    dnl Find libraries needed to link lib/frexpl.c.
+    if test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 1; then
+      AC_REQUIRE([gl_FUNC_FREXP])
+      FREXPL_LIBM="$FREXP_LIBM"
+    else
+      FREXPL_LIBM=
+    fi
+  fi
+  AC_SUBST([FREXPL_LIBM])
+])
+
+AC_DEFUN([gl_FUNC_FREXPL_NO_LIBM],
+[
+  AC_REQUIRE([gl_MATH_H_DEFAULTS])
+  AC_REQUIRE([gl_LONG_DOUBLE_VS_DOUBLE])
+  dnl Check whether it's declared.
+  dnl Mac OS X 10.3 has frexpl() in libc but doesn't declare it in <math.h>.
+  AC_CHECK_DECL([frexpl], , [HAVE_DECL_FREXPL=0], [[#include <math.h>]])
+  if test $HAVE_DECL_FREXPL = 1; then
+    gl_CHECK_FREXPL_NO_LIBM
+    if test $gl_cv_func_frexpl_no_libm = yes; then
+      gl_FUNC_FREXPL_WORKS
+      case "$gl_cv_func_frexpl_works" in
+        *yes) gl_func_frexpl_no_libm=yes ;;
+        *)    gl_func_frexpl_no_libm=no; REPLACE_FREXPL=1 ;;
+      esac
+    else
+      gl_func_frexpl_no_libm=no
+      dnl Set REPLACE_FREXPL here because the system may have frexpl in libm.
+      REPLACE_FREXPL=1
+    fi
+    if test $gl_func_frexpl_no_libm = yes; then
+      AC_DEFINE([HAVE_FREXPL_IN_LIBC], [1],
+        [Define if the frexpl() function is available in libc.])
+    fi
+  fi
+])
+
+dnl Test whether frexpl() can be used without linking with libm.
+dnl Set gl_cv_func_frexpl_no_libm to 'yes' or 'no' accordingly.
+AC_DEFUN([gl_CHECK_FREXPL_NO_LIBM],
+[
+  AC_CACHE_CHECK([whether frexpl() can be used without linking with libm],
+    [gl_cv_func_frexpl_no_libm],
+    [
+      AC_LINK_IFELSE(
+        [AC_LANG_PROGRAM(
+           [[#include <math.h>
+             long double x;]],
+           [[int e; return frexpl (x, &e) > 0;]])],
+        [gl_cv_func_frexpl_no_libm=yes],
+        [gl_cv_func_frexpl_no_libm=no])
+    ])
+])
+
+dnl Test whether frexpl() works on finite numbers (this fails on
+dnl Mac OS X 10.4/PowerPC, on AIX 5.1, and on BeOS), on denormalized numbers
+dnl (this fails on Mac OS X 10.5/i386), and also on infinite numbers (this
+dnl fails e.g. on IRIX 6.5 and mingw).
+AC_DEFUN([gl_FUNC_FREXPL_WORKS],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether frexpl works], [gl_cv_func_frexpl_works],
+    [
+      AC_RUN_IFELSE(
+        [AC_LANG_SOURCE([[
+#include <float.h>
+#include <math.h>
+/* Override the values of <float.h>, like done in float.in.h.  */
+#if defined __i386__ && (defined __BEOS__ || defined __OpenBSD__)
+# undef LDBL_MIN_EXP
+# define LDBL_MIN_EXP    (-16381)
+#endif
+#if defined __i386__ && (defined __FreeBSD__ || defined __DragonFly__)
+# undef LDBL_MIN_EXP
+# define LDBL_MIN_EXP    (-16381)
+#endif
+#if (defined _ARCH_PPC || defined _POWER) && defined _AIX && (LDBL_MANT_DIG == 106) && defined __GNUC__
+# undef LDBL_MIN_EXP
+# define LDBL_MIN_EXP DBL_MIN_EXP
+#endif
+#if defined __sgi && (LDBL_MANT_DIG >= 106)
+# if defined __GNUC__
+#  undef LDBL_MIN_EXP
+#  define LDBL_MIN_EXP DBL_MIN_EXP
+# endif
+#endif
+extern
+#ifdef __cplusplus
+"C"
+#endif
+long double frexpl (long double, int *);
+long double zero = 0.0L;
+int main()
+{
+  int result = 0;
+  volatile long double x;
+  /* Test on finite numbers that fails on AIX 5.1.  */
+  x = 16.0L;
+  {
+    int exp = -9999;
+    frexpl (x, &exp);
+    if (exp != 5)
+      result |= 1;
+  }
+  /* Test on finite numbers that fails on Mac OS X 10.4, because its frexpl
+     function returns an invalid (incorrectly normalized) value: it returns
+               y = { 0x3fe028f5, 0xc28f5c28, 0x3c9eb851, 0xeb851eb8 }
+     but the correct result is
+          0.505L = { 0x3fe028f5, 0xc28f5c29, 0xbc547ae1, 0x47ae1480 }  */
+  x = 1.01L;
+  {
+    int exp = -9999;
+    long double y = frexpl (x, &exp);
+    if (!(exp == 1 && y == 0.505L))
+      result |= 2;
+  }
+  /* Test on large finite numbers.  This fails on BeOS at i = 16322, while
+     LDBL_MAX_EXP = 16384.
+     In the loop end test, we test x against Infinity, rather than comparing
+     i with LDBL_MAX_EXP, because BeOS <float.h> has a wrong LDBL_MAX_EXP.  */
+  {
+    int i;
+    for (i = 1, x = 1.0L; x != x + x; i++, x *= 2.0L)
+      {
+        int exp = -9999;
+        frexpl (x, &exp);
+        if (exp != i)
+          {
+            result |= 4;
+            break;
+          }
+      }
+  }
+  /* Test on denormalized numbers.  */
+  {
+    int i;
+    for (i = 1, x = 1.0L; i >= LDBL_MIN_EXP; i--, x *= 0.5L)
+      ;
+    if (x > 0.0L)
+      {
+        int exp;
+        long double y = frexpl (x, &exp);
+        /* On machines with IEEE854 arithmetic: x = 1.68105e-4932,
+           exp = -16382, y = 0.5.  On Mac OS X 10.5: exp = -16384, y = 0.5.  */
+        if (exp != LDBL_MIN_EXP - 1)
+          result |= 8;
+      }
+  }
+  /* Test on infinite numbers.  */
+  /* The Microsoft MSVC 14 compiler chokes on the expression 1.0 / 0.0.  */
+  x = 1.0L / zero;
+  {
+    int exp;
+    long double y = frexpl (x, &exp);
+    if (y != x)
+      result |= 16;
+  }
+  return result;
+}]])],
+        [gl_cv_func_frexpl_works=yes],
+        [gl_cv_func_frexpl_works=no],
+        [
+changequote(,)dnl
+         case "$host_os" in
+           aix | aix[3-6]* | beos* | darwin* | irix* | mingw* | windows* | pw*)
+              gl_cv_func_frexpl_works="guessing no";;
+           *) gl_cv_func_frexpl_works="guessing yes";;
+         esac
+changequote([,])dnl
+        ])
+    ])
+])