Merge branch 'fix/MissingFldError' into 'master'

Fix error message for missing fld files

This should fix #35, which is related to some Hdf5 errors being displayed instead of a nice error message when we try to use an .fld file which does not exist.

See merge request !689

CHANGELOG.md

@@ -64,6 +64,7 @@ v4.3.4
   number of planes per process (!666)
 - Fix compilation with NEKTAR_USE_MESHGEN option
 - Fix IterativeFull solver in parallel (!685)
+- Fix error message for missing fld file (!689)
 
 **IncNavierStokesSolver:**
 - Fix 2nd order time-integration for VCSMapping (!687)

library/LibUtilities/BasicUtils/FieldIO.cpp

@@ -127,6 +127,7 @@ const std::string FieldIO::GetFileType(const std::string &filename,
             0x89, 0x48, 0x44, 0x46, 0x0d, 0x0a, 0x1a, 0x0a};
 
         std::ifstream datafile(datafilename.c_str(), ios_base::binary);
+        ASSERTL0(datafile.good(), "Unable to open file: " + filename);
 
         ioType = eHDF5;
         for (unsigned i = 0; i < 8 && datafile.good(); ++i)