configure: check if feenableexcept is actually working

Not all processors will signal floating point exceptions even when
told so, for example the Raspberry Pi as Dave Richards pointed out on
the ecl-devel mailing list.

src/aclocal.m4

@@ -939,6 +939,53 @@ if test $ECL_WORKING_ENVIRON = yes ; then
 fi
 ])
 
+dnl
+dnl --------------------------------------------------------------
+dnl Check if we have feenableexcept and the hardware generates
+dnl floating point exceptions.
+dnl
+AC_DEFUN(ECL_FLOATING_POINT_EXCEPTIONS,[
+  if test "${with_fpe}" = "yes" ; then
+  AC_MSG_CHECKING(for working feenableexcept)
+  saved_libs="${LIBS}"
+  LIBS="-lm"
+  AC_RUN_IFELSE([AC_LANG_SOURCE([[
+
+#define _GNU_SOURCE
+#include <fenv.h>
+#include <signal.h>
+#include <stdlib.h>
+
+const int traps = FE_DIVBYZERO | FE_OVERFLOW;
+
+void fpe_handler(int code) {
+	if (code == SIGFPE)
+		exit(0);
+}
+
+double raises_fpe(double x) {
+	return x / 0.0;
+}
+
+int main() {
+	signal(SIGFPE, fpe_handler);
+	feclearexcept(traps);
+	feenableexcept(traps);
+	raises_fpe(1.0);
+	return 1;
+}
+]])],
+  [AC_DEFINE([HAVE_FEENABLEEXCEPT], [], [feenableexcept works])
+   AC_MSG_RESULT(yes)],
+  [AC_MSG_RESULT(no)],
+  [AC_MSG_RESULT(only checking if feenableexcept is present due to cross compilation)
+   AC_CHECK_DECL([feenableexcept],
+                 [AC_DEFINE(HAVE_FEENABLEEXCEPT,[],[feenableexcept is declared])],
+                 [],
+                 [#include <fenv.h>])])
+  LIBS="${saved_libs}"
+  fi])
+
 dnl ----------------------------------------------------------------------
 dnl Configure libatomic-ops
 dnl

src/configure

@@ -741,6 +741,7 @@ infodir
 docdir
 oldincludedir
 includedir
+runstatedir
 localstatedir
 sharedstatedir
 sysconfdir
@@ -866,6 +867,7 @@ datadir='${datarootdir}'
 sysconfdir='${prefix}/etc'
 sharedstatedir='${prefix}/com'
 localstatedir='${prefix}/var'
+runstatedir='${localstatedir}/run'
 includedir='${prefix}/include'
 oldincludedir='/usr/include'
 docdir='${datarootdir}/doc/${PACKAGE_TARNAME}'
@@ -1118,6 +1120,15 @@ do
   | -silent | --silent | --silen | --sile | --sil)
     silent=yes ;;
 
+  -runstatedir | --runstatedir | --runstatedi | --runstated \
+  | --runstate | --runstat | --runsta | --runst | --runs \
+  | --run | --ru | --r)
+    ac_prev=runstatedir ;;
+  -runstatedir=* | --runstatedir=* | --runstatedi=* | --runstated=* \
+  | --runstate=* | --runstat=* | --runsta=* | --runst=* | --runs=* \
+  | --run=* | --ru=* | --r=*)
+    runstatedir=$ac_optarg ;;
+
   -sbindir | --sbindir | --sbindi | --sbind | --sbin | --sbi | --sb)
     ac_prev=sbindir ;;
   -sbindir=* | --sbindir=* | --sbindi=* | --sbind=* | --sbin=* \
@@ -1255,7 +1266,7 @@ fi
 for ac_var in	exec_prefix prefix bindir sbindir libexecdir datarootdir \
 		datadir sysconfdir sharedstatedir localstatedir includedir \
 		oldincludedir docdir infodir htmldir dvidir pdfdir psdir \
-		libdir localedir mandir
+		libdir localedir mandir runstatedir
 do
   eval ac_val=\$$ac_var
   # Remove trailing slashes.
@@ -1408,6 +1419,7 @@ Fine tuning of the installation directories:
   --sysconfdir=DIR        read-only single-machine data [PREFIX/etc]
   --sharedstatedir=DIR    modifiable architecture-independent data [PREFIX/com]
   --localstatedir=DIR     modifiable single-machine data [PREFIX/var]
+  --runstatedir=DIR       modifiable per-process data [LOCALSTATEDIR/run]
   --libdir=DIR            object code libraries [EPREFIX/lib]
   --includedir=DIR        C header files [PREFIX/include]
   --oldincludedir=DIR     C header files for non-gcc [/usr/include]
@@ -8996,6 +9008,8 @@ main ()
     if (*(data + i) != *(data3 + i))
       return 14;
   close (fd);
+  free (data);
+  free (data3);
   return 0;
 }
 _ACEOF
@@ -9443,17 +9457,6 @@ _ACEOF
 fi
 done
 
-ac_fn_c_check_decl "$LINENO" "feenableexcept" "ac_cv_have_decl_feenableexcept" "#include <fenv.h>
-"
-if test "x$ac_cv_have_decl_feenableexcept" = xyes; then :
-
-$as_echo "#define HAVE_FEENABLEEXCEPT /**/" >>confdefs.h
-
-else
-  { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: feenableexcept not declared: disabling floating point exceptions" >&5
-$as_echo "$as_me: WARNING: feenableexcept not declared: disabling floating point exceptions" >&2;}
-fi
-
 
 for ac_func in expf powf logf sqrtf cosf sinf tanf sinhf coshf tanhf \
                 floorf ceilf fabsf frexpf ldexpf log1p log1pf log1pl \
@@ -9537,6 +9540,70 @@ fi
 
 
 
+  if test "${with_fpe}" = "yes" ; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for working feenableexcept" >&5
+$as_echo_n "checking for working feenableexcept... " >&6; }
+  saved_libs="${LIBS}"
+  LIBS="-lm"
+  if test "$cross_compiling" = yes; then :
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: only checking if feenableexcept is present due to cross compilation" >&5
+$as_echo "only checking if feenableexcept is present due to cross compilation" >&6; }
+   ac_fn_c_check_decl "$LINENO" "feenableexcept" "ac_cv_have_decl_feenableexcept" "#include <fenv.h>
+"
+if test "x$ac_cv_have_decl_feenableexcept" = xyes; then :
+
+$as_echo "#define HAVE_FEENABLEEXCEPT /**/" >>confdefs.h
+
+fi
+
+else
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+
+#define _GNU_SOURCE
+#include <fenv.h>
+#include <signal.h>
+#include <stdlib.h>
+
+const int traps = FE_DIVBYZERO | FE_OVERFLOW;
+
+void fpe_handler(int code) {
+	if (code == SIGFPE)
+		exit(0);
+}
+
+double raises_fpe(double x) {
+	return x / 0.0;
+}
+
+int main() {
+	signal(SIGFPE, fpe_handler);
+	feclearexcept(traps);
+	feenableexcept(traps);
+	raises_fpe(1.0);
+	return 1;
+}
+
+_ACEOF
+if ac_fn_c_try_run "$LINENO"; then :
+
+$as_echo "#define HAVE_FEENABLEEXCEPT /**/" >>confdefs.h
+
+   { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+rm -f core *.core core.conftest.* gmon.out bb.out conftest$ac_exeext \
+  conftest.$ac_objext conftest.beam conftest.$ac_ext
+fi
+
+  LIBS="${saved_libs}"
+  fi
+
+
 
 if test ${with_cxx} = "no" ; then
   ECL_CC=${CC}

src/configure.ac

@@ -738,10 +738,6 @@ dnl !!! end autoscan
 AC_CHECK_FUNCS( [nanosleep alarm times select setenv putenv] \
                 [lstat mkstemp sigprocmask isatty tzset] \
                 [gettimeofday getrusage system] )
-AC_CHECK_DECL([feenableexcept],
-              [AC_DEFINE(HAVE_FEENABLEEXCEPT,[],[feenableexcept is available])],
-              [AC_MSG_WARN(feenableexcept not declared: disabling floating point exceptions)],
-              [#include <fenv.h>])
 
 AC_CHECK_FUNCS( [expf powf logf sqrtf cosf sinf tanf sinhf coshf tanhf] \
                 [floorf ceilf fabsf frexpf ldexpf log1p log1pf log1pl] \
@@ -756,6 +752,8 @@ AC_CHECK_HEADER( [sys/mman.h],
 
 ECL_POSIX_ENVIRON
 
+ECL_FLOATING_POINT_EXCEPTIONS
+
 dnl =====================================================================
 dnl Checks for system services
 

src/ecl/configpre.h

@@ -303,7 +303,7 @@
 /* Define to 1 if you have the <fcntl.h> header file. */
 #undef HAVE_FCNTL_H
 
-/* feenableexcept is available */
+/* feenableexcept works */
 #undef HAVE_FEENABLEEXCEPT
 
 /* Define to 1 if you have the <fenv.h> header file. */