X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Ftruncf.m4;h=e0fe36a1586926fba472d2e620c71541e21ccf7e;hb=533101a268dc5015a140ff4695d8eeb04fbe57b6;hp=4d5099f83fdad9dd540a25cdd9b8275e623626f1;hpb=b2e2010c7c902235b5efb5bd3c6529f61b093aa4;p=gnulib.git

diff --git a/m4/truncf.m4 b/m4/truncf.m4
index 4d5099f83..e0fe36a15 100644
--- a/m4/truncf.m4
+++ b/m4/truncf.m4
@@ -1,48 +1,95 @@
-# truncf.m4 serial 1
-dnl Copyright (C) 2007, 2009, 2010 Free Software Foundation, Inc.
+# truncf.m4 serial 9
+dnl Copyright (C) 2007, 2010-2013 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_TRUNCF],
 [
+  m4_divert_text([DEFAULTS], [gl_truncf_required=plain])
   AC_REQUIRE([gl_MATH_H_DEFAULTS])
   dnl Persuade glibc <math.h> to declare truncf().
   AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
   dnl Test whether truncf() is declared.
-  AC_CHECK_DECLS([truncf], , , [#include <math.h>])
+  AC_CHECK_DECLS([truncf], , , [[#include <math.h>]])
   if test "$ac_cv_have_decl_truncf" = yes; then
     dnl Test whether truncf() can be used without libm.
     TRUNCF_LIBM=?
-    AC_TRY_LINK([
-       #ifndef __NO_MATH_INLINES
-       # define __NO_MATH_INLINES 1 /* for glibc */
-       #endif
-       #include <math.h>
-       float x;],
-      [x = truncf(x);],
+    AC_LINK_IFELSE(
+      [AC_LANG_PROGRAM(
+         [[#ifndef __NO_MATH_INLINES
+           # define __NO_MATH_INLINES 1 /* for glibc */
+           #endif
+           #include <math.h>
+           float x;]],
+         [[x = truncf(x);]])],
       [TRUNCF_LIBM=])
     if test "$TRUNCF_LIBM" = "?"; then
       save_LIBS="$LIBS"
       LIBS="$LIBS -lm"
-      AC_TRY_LINK([
-         #ifndef __NO_MATH_INLINES
-         # define __NO_MATH_INLINES 1 /* for glibc */
-         #endif
-         #include <math.h>
-         float x;],
-        [x = truncf(x);],
+      AC_LINK_IFELSE(
+        [AC_LANG_PROGRAM(
+           [[#ifndef __NO_MATH_INLINES
+             # define __NO_MATH_INLINES 1 /* for glibc */
+             #endif
+             #include <math.h>
+             float x;]],
+           [[x = truncf(x);]])],
         [TRUNCF_LIBM="-lm"])
       LIBS="$save_LIBS"
     fi
     if test "$TRUNCF_LIBM" = "?"; then
       TRUNCF_LIBM=
     fi
+    m4_ifdef([gl_FUNC_TRUNCF_IEEE], [
+      if test $gl_truncf_required = ieee && test $REPLACE_TRUNCF = 0; then
+        AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+        AC_CACHE_CHECK([whether truncf works according to ISO C 99 with IEC 60559],
+          [gl_cv_func_truncf_ieee],
+          [
+            save_LIBS="$LIBS"
+            LIBS="$LIBS $TRUNCF_LIBM"
+            AC_RUN_IFELSE(
+              [AC_LANG_SOURCE([[
+#ifndef __NO_MATH_INLINES
+# define __NO_MATH_INLINES 1 /* for glibc */
+#endif
+#include <math.h>
+]gl_FLOAT_MINUS_ZERO_CODE[
+]gl_FLOAT_SIGNBIT_CODE[
+static float dummy (float f) { return 0; }
+int main (int argc, char *argv[])
+{
+  float (*my_truncf) (float) = argc ? truncf : dummy;
+  /* Test whether truncf (-0.0f) is -0.0f.  */
+  if (signbitf (minus_zerof) && !signbitf (my_truncf (minus_zerof)))
+    return 1;
+  return 0;
+}
+              ]])],
+              [gl_cv_func_truncf_ieee=yes],
+              [gl_cv_func_truncf_ieee=no],
+              [case "$host_os" in
+                         # Guess yes on glibc systems.
+                 *-gnu*) gl_cv_func_truncf_ieee="guessing yes" ;;
+                         # If we don't know, assume the worst.
+                 *)      gl_cv_func_truncf_ieee="guessing no" ;;
+               esac
+              ])
+            LIBS="$save_LIBS"
+          ])
+        case "$gl_cv_func_truncf_ieee" in
+          *yes) ;;
+          *) REPLACE_TRUNCF=1 ;;
+        esac
+      fi
+    ])
   else
     HAVE_DECL_TRUNCF=0
-    AC_LIBOBJ([truncf])
+  fi
+  if test $HAVE_DECL_TRUNCF = 0 || test $REPLACE_TRUNCF = 1; then
+    dnl No libraries are needed to link lib/truncf.c.
     TRUNCF_LIBM=
   fi
-  AC_SUBST([HAVE_DECL_TRUNCF])
   AC_SUBST([TRUNCF_LIBM])
 ])