From 761f8376a314c6d00bb275bf1a9cae90e04bef4e Mon Sep 17 00:00:00 2001
From: Wolfgang Bangerth <bangerth@math.tamu.edu>
Date: Tue, 28 Jul 2015 16:32:20 -0500
Subject: [PATCH] Detect whether we can use floating point exceptions.

---
 cmake/checks/check_02_system_features.cmake | 36 +++++++++++++++++++++
 include/deal.II/base/config.h.in            |  1 +
 2 files changed, 37 insertions(+)

diff --git a/cmake/checks/check_02_system_features.cmake b/cmake/checks/check_02_system_features.cmake
index cd58f41416..33aaccc9f0 100644
--- a/cmake/checks/check_02_system_features.cmake
+++ b/cmake/checks/check_02_system_features.cmake
@@ -19,6 +19,7 @@
 #   DEAL_II_HAVE_GETHOSTNAME
 #   DEAL_II_HAVE_GETPID
 #   DEAL_II_HAVE_JN
+#   DEAL_II_HAVE_FP_EXCEPTIONS
 #   DEAL_II_HAVE_SYS_RESOURCE_H
 #   DEAL_II_HAVE_SYS_TIME_H
 #   DEAL_II_HAVE_SYS_TIMES_H
@@ -67,6 +68,41 @@ IF(NOT m_LIBRARY MATCHES "-NOTFOUND")
 ENDIF()
 
 
+#
+# Check that we can use feenableexcept. Sets DEAL_II_HAVE_FP_EXCEPTIONS
+#
+# The test is a bit more complicated because we also check that no garbage
+# exception is thrown if we convert -std::numeric_limits<double>::max to a
+# string. This sadly happens with some compiler support libraries :-(
+
+INCLUDE (CheckCXXSourceRuns)
+
+CHECK_CXX_SOURCE_RUNS("
+  #include <fenv.h>
+  #include <limits>
+  #include <sstream>
+
+  int main()
+  {
+    feenableexcept(FE_DIVBYZERO|FE_INVALID);
+    std::ostringstream description;
+    const double lower_bound = -std::numeric_limits<double>::max();  
+
+    description << lower_bound;
+
+    return 0;
+  }
+  " 
+  _HAVE_FP_EXCEPTIONS)
+
+IF(_HAVE_FP_EXCEPTIONS)
+  MESSAGE(STATUS "Checking for Floating Point Exception macros -- Success")
+  SET(DEAL_II_HAVE_FP_EXCEPTIONS 1)
+ELSE()
+  MESSAGE(STATUS "Checking for Floating Point Exception macros -- Failed")
+ENDIF()
+
+
 ########################################################################
 #                                                                      #
 #                        Mac OSX specific setup:                       #
diff --git a/include/deal.II/base/config.h.in b/include/deal.II/base/config.h.in
index 09fbfb319c..05a6ae90cd 100644
--- a/include/deal.II/base/config.h.in
+++ b/include/deal.II/base/config.h.in
@@ -128,6 +128,7 @@
 #cmakedefine DEAL_II_HAVE_GETPID
 #cmakedefine DEAL_II_HAVE_TIMES
 #cmakedefine DEAL_II_HAVE_JN
+#cmakedefine DEAL_II_HAVE_FP_EXCEPTIONS
 
 #cmakedefine DEAL_II_MSVC
 
-- 
2.39.5