Bugfix 2531 compilation errors (#2533)

* Resolve error: more than one instance of overloaded function isnan matches the argument list

* Ensure RTD build passes

* Added std:: in front of isnan for compilation on Hera

* Add -std=c++11 to CXXFLAGS

* Added note about C++11

.readthedocs.yaml

@@ -13,7 +13,7 @@ build:
   os: ubuntu-22.04
   tools:
     python: "3.10"
-    
+
 # Optionally set the version of Python and requirements required to build your
 # docs
 python:

configure.ac

@@ -1086,6 +1086,9 @@ AM_CONDITIONAL([ENABLE_DEVELOPMENT], [test -n "$MET_DEVELOPMENT"])
 
 CPPFLAGS=$CPPFLAGS' -DMET_BASE="\"$(pkgdatadir)\""'
 
+# Add -std=c++11 to CXXFLAGS                                                                                                                                                 
+CXXFLAGS=$CXXFLAGS' -std=c++11'
+
 # Define other variables for the makefiles
 
 AC_SUBST(FC_LIBS, [-lgfortran])

docs/Users_Guide/installation.rst

@@ -21,6 +21,8 @@ Programming Languages
 
 The MET package, including MET-TC, is written primarily in C/C++ in order to be compatible with an extensive verification code base in C/C++ already in existence. In addition, the object-based MODE and MODE-TD verification tools rely heavily on the object-oriented aspects of C++. Knowledge of C/C++ is not necessary to use the MET package. The MET package has been designed to be highly configurable through the use of ASCII configuration files, enabling a great deal of flexibility without the need for source code modifications.
 
+With the release of MET-11.1.0, C++11 is now the minimum required version of the C++ programming language standard.
+
 NCEP's BUFRLIB is written entirely in Fortran. The portion of MET that handles the interface to the BUFRLIB for reading PrepBUFR point observation files is also written in Fortran.
 
 The MET package is intended to be a tool for the modeling community to use and adapt. As users make upgrades and improvements to the tools, they are encouraged to offer those upgrades to the broader community by offering feedback to the developers.

src/libcode/vx_grid/goes_grid.cc

@@ -493,13 +493,13 @@ void GoesImagerData::compute_lat_lon()
                 mlog << Error << method_name << " index=" << index
                      << "  too big than " << buf_len << "\n";
             else {
-               if (isnan(lat_rad)) lat = bad_data_float;
+	       if (std::isnan(lat_rad)) lat = bad_data_float;
                else {
                   lat = lat_rad * deg_per_rad;
                   if (lat > lat_max) {lat_max = lat; idx_lat_max = index; }
                   if (lat < lat_min) {lat_min = lat; idx_lat_min = index; }
                }
-               if (isnan(lon_rad)) lon = bad_data_float;
+	       if (std::isnan(lon_rad)) lon = bad_data_float;
                else {
                   lon = lon_of_projection_origin - (lon_rad * deg_per_rad);
                   if (lon > lon_max) {lon_max = lon; idx_lon_max = index; }

src/libcode/vx_statistics/compute_stats.cc

@@ -1596,7 +1596,7 @@ void compute_aggregated_seeps_grid(const DataPlane &fcst_dp, const DataPlane &ob
                   else count_diagonal++;
                }
                seeps_score = seeps_mpr->score;
-               if (isnan(seeps_score)) {
+               if (std::isnan(seeps_score)) {
                   nan_count++;
                   seeps_score = bad_data_double;
                }

src/libcode/vx_statistics/contable_stats.cc

@@ -1146,7 +1146,7 @@ for (j=0; j<Nrows; ++j)  {
    //  replace nan with bad data
    //
 
-if (isnan(sum))  sum = bad_data_double;
+ if (std::isnan(sum))  sum = bad_data_double;
 
    //
    //  done