Add isnand module.

[gnulib.git] / m4 / isnand.m4

diff --git a/m4/isnand.m4 b/m4/isnand.m4
index 7783b42..083051b 100644 (file)
--- a/m4/isnand.m4
+++ b/m4/isnand.m4
@@ -1,13 +1,80 @@
-# isnand.m4 serial 2
+# isnand.m4 serial 3
 dnl Copyright (C) 2007-2008 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.
 
+dnl Check how to get or define isnand().
+AC_DEFUN([gl_FUNC_ISNAND],
+[
+  ISNAND_LIBM=
+  gl_HAVE_ISNAND_NO_LIBM
+  if test $gl_cv_func_isnand_no_libm = no; then
+    gl_HAVE_ISNAND_IN_LIBM
+    if test $gl_cv_func_isnand_in_libm = yes; then
+      ISNAND_LIBM=-lm
+    fi
+  fi
+  dnl The variable gl_func_isnand set here is used by isnan.m4.
+  if test $gl_cv_func_isnand_no_libm = yes \
+     || test $gl_cv_func_isnand_in_libm = yes; then
+    gl_func_isnand=yes
+    AC_DEFINE([HAVE_ISNAND], 1,
+      [Define if the isnan(double) function is available.])
+  else
+    gl_func_isnand=no
+    gl_BUILD_ISNAND
+  fi
+  AC_SUBST([ISNAND_LIBM])
+])
+
 dnl Check how to get or define isnand() without linking with libm.
 
 AC_DEFUN([gl_FUNC_ISNAND_NO_LIBM],
 [
+  gl_HAVE_ISNAND_NO_LIBM
+  if test $gl_cv_func_isnand_no_libm = yes; then
+    AC_DEFINE([HAVE_ISNAND_IN_LIBC], 1,
+      [Define if the isnan(double) function is available in libc.])
+  else
+    gl_BUILD_ISNAND
+  fi
+])
+
+dnl Pull in replacement isnand definition.
+AC_DEFUN([gl_BUILD_ISNAND],
+[
+  AC_LIBOBJ([isnand])
+  gl_DOUBLE_EXPONENT_LOCATION
+])
+
+dnl Test whether isnand() can be used with libm.
+
+AC_DEFUN([gl_HAVE_ISNAND_IN_LIBM],
+[
+  AC_CACHE_CHECK([whether isnan(double) can be used with libm],
+    [gl_cv_func_isnand_in_libm],
+    [
+      save_LIBS="$LIBS"
+      LIBS="$LIBS -lm"
+      AC_TRY_LINK([#include <math.h>
+                   #if __GNUC__ >= 4
+                   # undef isnand
+                   # define isnand(x) __builtin_isnand ((double)(x))
+                   #elif defined isnan
+                   # undef isnand
+                   # define isnand(x) isnan ((double)(x))
+                   #endif
+                   double x;],
+                  [return isnand (x);],
+        [gl_cv_func_isnand_in_libm=yes],
+        [gl_cv_func_isnand_in_libm=no])
+      LIBS="$save_LIBS"
+    ])
+])
+
+AC_DEFUN([gl_HAVE_ISNAND_NO_LIBM],
+[
   AC_CACHE_CHECK([whether isnan(double) can be used without linking with libm],
     [gl_cv_func_isnand_no_libm],
     [
@@ -24,13 +91,6 @@ AC_DEFUN([gl_FUNC_ISNAND_NO_LIBM],
         [gl_cv_func_isnand_no_libm=yes],
         [gl_cv_func_isnand_no_libm=no])
     ])
-  if test $gl_cv_func_isnand_no_libm = yes; then
-    AC_DEFINE([HAVE_ISNAND_IN_LIBC], 1,
-      [Define if the isnan(double) function is available in libc.])
-  else
-    AC_LIBOBJ([isnand])
-    gl_DOUBLE_EXPONENT_LOCATION
-  fi
 ])
 
 AC_DEFUN([gl_DOUBLE_EXPONENT_LOCATION],