From 08fe85b4cda03f9106381cbb251a7d363c5e6626 Mon Sep 17 00:00:00 2001
From: Harry Moffat <hkmoffa@sandia.gov>
Date: Tue, 26 Aug 2014 17:55:44 +0000
Subject: [PATCH] Check for fenv.h availability. Apparently, MS visual doesn't
 have C99 support before 2013, so previous commit didn't compile on MSVISUAL.
 If fenv.h not available, program now error exits if fenv functions are
 requested.

---
 SConstruct                       | 12 ++++++++++++
 include/cantera/base/config.h.in |  2 ++
 src/base/ctexceptions.cpp        |  6 ++++++
 src/thermo/GibbsExcessVPSSTP.cpp |  5 +++++
 4 files changed, 25 insertions(+)

diff --git a/SConstruct b/SConstruct
index d8d4a5406..9032bd90a 100644
--- a/SConstruct
+++ b/SConstruct
@@ -770,6 +770,12 @@ def get_expression_value(includes, expression):
 
 env['HAS_TIMES_H'] = conf.CheckCHeader('sys/times.h', '""')
 env['HAS_UNISTD_H'] = conf.CheckCHeader('unistd.h', '""')
+#
+# Check to see if the compiler supports C99 fenv.h
+#      Apparently, the only compiler not to is MS visual before 2013
+#
+env['HAS_FENV_H'] = conf.CheckCHeader('fenv.h', '""')
+
 env['HAS_MATH_H_ERF'] = conf.CheckDeclaration('erf', '#include <math.h>', 'C++')
 
 env['HAS_GLOBAL_ISNAN'] = conf.CheckStatement('::isnan(1.0)', '#include <cmath>')
@@ -1210,6 +1216,12 @@ cdefine('USE_GLOBAL_ISNAN', 'HAS_GLOBAL_ISNAN')
 cdefine('USE_STD_ISNAN', 'HAS_STD_ISNAN')
 cdefine('USE_UNDERSCORE_ISNAN', 'HAS_UNDERSCORE_ISNAN')
 
+#  this turns on HAS_FENV_H
+if env['HAS_FENV_H']:
+    configh['HAS_FENV_H'] = 1
+else:
+    configh['HAS_FENV_H'] = None
+
 config_h = env.Command('include/cantera/base/config.h',
                        'include/cantera/base/config.h.in',
                        ConfigBuilder(configh))
diff --git a/include/cantera/base/config.h.in b/include/cantera/base/config.h.in
index 977fc2a9d..bf0739e0b 100644
--- a/include/cantera/base/config.h.in
+++ b/include/cantera/base/config.h.in
@@ -76,6 +76,8 @@ typedef  int          ftnlen;       // Fortran hidden string length type
 %(USE_GLOBAL_ISNAN)s
 %(USE_UNDERSCORE_ISNAN)s
 
+%(HAS_FENV_H)s
+
 // This define is needed to account for the variability for how
 // static variables in templated classes are defined. Right now
 // this is only turned on for the SunPro compiler on Solaris.
diff --git a/src/base/ctexceptions.cpp b/src/base/ctexceptions.cpp
index d77352195..b9a9e64b3 100644
--- a/src/base/ctexceptions.cpp
+++ b/src/base/ctexceptions.cpp
@@ -5,7 +5,9 @@
 #include "cantera/base/global.h"
 #include "cantera/base/stringUtils.h"
 
+#ifdef HAVE_FENVH
 #include <fenv.h>
+#endif
 #include <sstream>
 #include <typeinfo>
 
@@ -78,16 +80,20 @@ std::string IndexError::getMessage() const
 }
 //============================================================================================================
 bool check_FENV_OverUnder_Flow() {
+#ifdef HAVE_FENV_H
      fexcept_t ff;
      fegetexceptflag(&ff, FE_OVERFLOW || FE_UNDERFLOW || FE_INVALID);
      if (ff) {
         return true;
      }
+#endif
      return false;
 };
 //============================================================================================================
 void clear_FENV() {
+#ifdef HAVE_FENV_H
      feclearexcept(FE_ALL_EXCEPT);
+#endif
 }
 //============================================================================================================
 
diff --git a/src/thermo/GibbsExcessVPSSTP.cpp b/src/thermo/GibbsExcessVPSSTP.cpp
index e7edd76e8..045f8a118 100644
--- a/src/thermo/GibbsExcessVPSSTP.cpp
+++ b/src/thermo/GibbsExcessVPSSTP.cpp
@@ -207,10 +207,15 @@ void GibbsExcessVPSSTP::getActivityCoefficients(doublereal* const ac) const
             ac[k] = exp(ac[k]);
         }
         if (realNumberRangeBehavior_ == FENV_CHECK_CTRB) {
+#ifdef HAVE_FENV_H
             if (check_FENV_OverUnder_Flow()) {
                 throw CanteraError("GibbsExcessVPSSTP::getActivityCoefficients()",
                                    "activity coefficient is over/underflowing");
             }
+#else
+            throw CanteraError("GibbsExcessVPSSTP::getActivityCoefficients()",
+                               "realNumberRangeBehavior_ == FENV_CHECK_CTRB not supported by compiler");
+#endif
         }
     }
 }