add support for trapping floating point exception as an optional compile time feature

we may make this a run time setting by connecting this code to a command.

src/main.cpp

@@ -18,6 +18,10 @@
 #include <stdio.h>
 #include <stdlib.h>
 
+#if defined(LAMMPS_TRAP_FPE) && defined(_GNU_SOURCE)
+#include <fenv.h>
+#endif
+
 using namespace LAMMPS_NS;
 
 /* ----------------------------------------------------------------------
@@ -28,6 +32,18 @@ int main(int argc, char **argv)
 {
   MPI_Init(&argc,&argv);
 
+// enable trapping selected floating point exceptions.
+// this uses GNU extensions and is only tested on Linux
+// therefore we make it depend on -D_GNU_SOURCE, too.
+
+#if defined(LAMMPS_TRAP_FPE) && defined(_GNU_SOURCE)
+  fesetenv(FE_NOMASK_ENV);
+  fedisableexcept(FE_ALL_EXCEPT);
+  feenableexcept(FE_DIVBYZERO);
+  feenableexcept(FE_INVALID);
+  feenableexcept(FE_OVERFLOW);
+#endif
+
 #ifdef LAMMPS_EXCEPTIONS
   try {
     LAMMPS *lammps = new LAMMPS(argc,argv,MPI_COMM_WORLD);