Implemented a fix for multiple concurrent file handles.

include/trick/MonteVarFile.hh

@@ -73,6 +73,10 @@ namespace Trick {
         /** The input file stream. */
         std::ifstream *input_file_stream; /**< \n trick_units(--) */
 
+        private:
+        // Used to store the current position of the stream for file opening and closing.
+        std::streampos stream_position;
+
         public:
         /**
          * Constructs a MonteVarFile with the specified name, file name, column, and units.

trick_source/sim_services/MonteCarlo/MonteVarFile.cpp

@@ -34,6 +34,17 @@ std::string Trick::MonteVarFile::describe_variable() {
 }
 
 std::string Trick::MonteVarFile::get_next_value() {
+
+    // Reopen the file if not open.
+    if(!input_file_stream->is_open()) {
+        input_file_stream->open(this->file_name.c_str(), std::ifstream::in);
+
+        // If the stream position has been set, re-open file to this position.
+        if(this->stream_position != NULL) {
+            input_file_stream->seekg(this->stream_position);
+        }
+    }
+
     if (input_file_stream->good()) {
         std::string line;
         // Skip the comments and empty lines in the data file.
@@ -47,6 +58,10 @@ std::string Trick::MonteVarFile::get_next_value() {
         }
         while(line[0] == '#' || line[0] == '\0');
 
+        // Store the current stream position and close the file.
+        this->stream_position = input_file_stream->tellg();
+        input_file_stream->close();
+
         // Count the number of columns in the input file.
         char *token;
         unsigned int ntokens = 0;