Correctly build argv with nullptr at the end

src/lammps.cpp

@@ -107,6 +107,15 @@ using namespace LAMMPS_NS;
  * The specifics of setting up and running a simulation are handled by the
  * individual component class instances. */
 
+/** Create a LAMMPS simulation instance
+ *
+ * \param args list of arguments
+ * \param communicator MPI communicator used by this LAMMPS instance
+ */
+LAMMPS::LAMMPS(argv & args, MPI_Comm communicator) :
+  LAMMPS(args.size(), argv_pointers(args).data(), communicator) {
+}
+
 /** Create a LAMMPS simulation instance
  *
  * The LAMMPS constructor starts up a simulation by allocating all
@@ -1464,3 +1473,17 @@ void LAMMPS::print_config(FILE *fp)
   }
   fputs("\n\n",fp);
 }
+
+/** Create vector of argv string pointers including terminating nullptr element
+ *
+ * \param args list of arguments
+ */
+std::vector<char*> LAMMPS::argv_pointers(argv & args){
+  std::vector<char*> r;
+  r.reserve(args.size()+1);
+  for(auto & a : args) {
+    r.push_back((char*)a.data());
+  }
+  r.push_back(nullptr);
+  return r;
+}