[TRNSYS-users] Error in cpp programming

Thu Jul 30 03:19:24 PDT 2009

Dear alone,

Reading TRNSYS external files from C or C++ is somewhat tricky. 

The problem comes from the fact that 

a)       the TRNSYS kernel (not the TYPE) will open the external file at the beginning of the simulation and (assign file handles)

b)       file handles are not interoperable between compilers (sometimes not even between the release and debug version of the same FORTRAN compiler)

To work around the problem, it has been proposed to use the special cards mechanism instead: 

1.	specify the file name as a special card
2.	read it and open() the file in the initialization of the C code
3.	close() it in the type at simulation stop

Recently, I implemented another method to use 'real' external files with TYPES written in C/C++. It is way bizarre, but works:

1.	A DLL, FileReader.dll, is implemented in FORTRAN; this Dll provides functions to read the next character for a given external file
2.	The C type implements a function to read the next line in a given external file based on 1. and uses the external file like a traditional type in FORTRAN would.

I provided the FileReader.DLLs for those who do not have a FORTRAN compiler and the C++ code implementing a class to access it follows (made with Compaq Visual FORTRAN for compatibility with the official TRNSYS 16.1 release):

ftp://ftp.cstb.fr/software/Trnsys/FileReader/

With this, you can just read the file in C++ like this:

                  double LUN;

                  LUN=par[0];

                  iunit=info[0];

                  itype=info[1];

                std::string code;

                TrnsysFileReader theReader;

                while (!theReader.Eof())

                  {

                        string tmp = theReader.ReadNextLine((int) LUN);

                        code.append(rtrim(tmp));

                        code.append("\r\n");

                  }

Hope this helps,

Werner

#include <cmath>

#include <fstream>

//#include "windows.h"

#include "TrnsysFileReader.h"         

typedef int (__cdecl* LPFNDLLFUNC1)(int*);

LPFNDLLFUNC1 lpfnDllFunc1; 

TrnsysFileReader::TrnsysFileReader()

{

        lpfProcFunction = NULL;

        TCHAR path[1024];

        GetModuleFileName(NULL, path, sizeof(path));

            std::string str = path;

            unsigned tmp1, tmp2;

            tmp1 = tmp2 = 0;

            for(unsigned i = 0; i < str.length(); i++)

            {

                  if(path[i] == '\\')

                  {

                        tmp2 = tmp1;

                        tmp1 = i;

                  }

            }

            str.resize(tmp2);

            #ifdef _DEBUG

                  str.append("\\Userlib\\DebugDLLs\\FileReader.dll");

            #else

                  str.append("\\Userlib\\ReleaseDLLs\\FileReader.dll");

            #endif

            hLibrary = LoadLibrary(str.c_str());

        eof = false;

        maxFileWidth=1000; // from TrnsysConstants.f90

      }

TrnsysFileReader::~TrnsysFileReader()

      {

          FreeLibrary(hLibrary);

      }

      bool TrnsysFileReader::Eof() 

      { 

        return eof;

      }

      int TrnsysFileReader::ReadNextChar(int LUN)

      {

        int c;

        if (hLibrary == NULL) return -1;

        lpfnDllFunc1 = (LPFNDLLFUNC1) GetProcAddress( hLibrary, 

                        "READNEXTCHAR");

        int ilun = (int) LUN;

        c = lpfnDllFunc1(&ilun);

            if(c == -2) throw std::bad_exception("Problème avec le fichier");

        if (c == -1) eof = true;

        return c;

      }

      std::string TrnsysFileReader::ReadFile(int LUN)

      {

        std::string result; 

        char c;

        while ((c = ReadNextChar(LUN)) && (!eof))

        {          

          std::string s;

          s.append(&c,1);

          result.append(s);

        }

        return result;

      }

      std::string TrnsysFileReader::ReadNextLine(int LUN)

      {

        std::string result; 

        char c;

        while ((c = ReadNextChar(LUN)) && (!eof) && (result.length() < (unsigned int)maxFileWidth-1))

        {          

          std::string s;

          s.append(&c,1);

          result.append(s);

        }

        return result;

      }

TrnsysFileReader.h :

#ifndef trnsyfilereaderincluded

#define trnsyfilereaderincluded

#include <cmath>

#include <fstream>

#include "windows.h"

#include <string.h>

#include "TRNSYS.h" //TRNSYS acess functions (allow to acess TIME etc.) 

typedef int (__cdecl* LPFNDLLFUNC1)(int*);

class TrnsysFileReader

{

private :

      HMODULE hLibrary;

      FARPROC lpfProcFunction;   

      bool eof;

      LPFNDLLFUNC1 lpfnDllFunc1; 

      int maxFileWidth;

public:

      TrnsysFileReader();

      ~TrnsysFileReader();

      bool Eof();

      int ReadNextChar(int LUN);

      std::string ReadNextLine(int LUN);

      std::string ReadFile(int LUN);

};

#endif

________________________________

De : rgaray at labein.es [mailto:rgaray at labein.es] 
Envoyé : mercredi 29 juillet 2009 17:38
À : LISTA DE CORREO USUARIOS TRNSYS 
Objet : [TRNSYS-users] Error in cpp programming

Dear All, 

I´m programming a new type in cpp and It gives an error I do not get to understand. I get an error in the fgets.c function. This function is an ordinary cpp function for reading an external file. 
I have previously debugged the code itself with a dummy application that called the dll and worked fine, but when I try to debug the dll with trnsys it crashes. 

Has anyone previously had this problem? 

I´m quite lost so any help will be appreciated. Thank You. 

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