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[gnulib.git] / m4 / frexpl.m4

diff --git a/m4/frexpl.m4 b/m4/frexpl.m4
index 361fd2d..dad5dd7 100644 (file)
--- a/m4/frexpl.m4
+++ b/m4/frexpl.m4
@@ -1,4 +1,4 @@
-# frexpl.m4 serial 1
+# frexpl.m4 serial 5
 dnl Copyright (C) 2007 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -36,12 +36,115 @@ AC_DEFUN([gl_FUNC_FREXPL],
   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; FREXPL_LIBM= ;;
+    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.])
     dnl Also check whether it's declared.
     dnl MacOS 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>])
   else
+    HAVE_DECL_FREXPL=0
     AC_LIBOBJ([frexpl])
   fi
+  AC_SUBST([FREXPL_LIBM])
+])
+
+AC_DEFUN([gl_FUNC_FREXPL_NO_LIBM],
+[
+  AC_REQUIRE([gl_MATH_H_DEFAULTS])
+  AC_CACHE_CHECK([whether frexpl() can be used without linking with libm],
+    [gl_cv_func_frexpl_no_libm],
+    [
+      AC_TRY_LINK([#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])
+    ])
+  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 $gl_func_frexpl_no_libm = yes; then
+    AC_DEFINE([HAVE_FREXPL_IN_LIBC], 1,
+      [Define if the frexpl() function is available in libc.])
+    dnl Also check whether it's declared.
+    dnl MacOS X 10.3 has frexpl() in libc but doesn't declare it in <math.h>.
+    AC_CHECK_DECL([frexpl], , [HAVE_DECL_FREXPL=0], [#include <math.h>])
+  else
+    HAVE_DECL_FREXPL=0
+    AC_LIBOBJ([frexpl])
+  fi
+])
+
+dnl Test whether frexpl() works on finite numbers (this fails on AIX 5.1 and
+dnl on BeOS) and also on infinite numbers (this fails e.g. on IRIX 6.5).
+AC_DEFUN([gl_FUNC_FREXPL_WORKS],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether frexpl works], [gl_cv_func_frexpl_works],
+    [
+      AC_TRY_RUN([
+#include <math.h>
+extern long double frexpl (long double, int *);
+int main()
+{
+  volatile long double x;
+  /* Test on finite numbers.  */
+  x = 16.0L;
+  {
+    int exp = -9999;
+    frexpl (x, &exp);
+    if (exp != 5)
+      return 1;
+  }
+  /* Test on large finite numbers.  This fails on BeOS at i = 16322, while
+     LDBL_MAX_EXP = 16384.
+     In the loop end test, we test x against Infinity, rather than comparing
+     i with LDBL_MAX_EXP, because BeOS <float.h> has a wrong LDBL_MAX_EXP.  */
+  {
+    int i;
+    for (i = 1, x = 1.0L; x != x + x; i++, x *= 2.0L)
+      {
+        int exp = -9999;
+        frexpl (x, &exp);
+        if (exp != i)
+          return 1;
+      }
+  }
+  /* Test on infinite numbers.  */
+  x = 1.0L / 0.0L;
+  {
+    int exp;
+    long double y = frexpl (x, &exp);
+    if (y != x)
+      return 1;
+  }
+  return 0;
+}], [gl_cv_func_frexpl_works=yes], [gl_cv_func_frexpl_works=no],
+      [case "$host_os" in
+         aix* | beos* | irix*) gl_cv_func_frexpl_works="guessing no";;
+         *)                    gl_cv_func_frexpl_works="guessing yes";;
+       esac
+      ])
+    ])
 ])