🚀 go-pugleaf

Hi,
not sure if this is the appropriate group. If not please redirect me.

I want to export some code for validating files to a DLL. Since I have
not written many DLLs yet I have some troubles/questions

1) I would like to use the std::string class for parameters of the
exported functions. Are there any issues I should be aware of with this?
The DLL will only be used from C++ code, most likely only from BCB.

2) The DLL .cpp file that BCB generates starts with a long comment
about using string (AnsiString?) parameters in exported functions.
Is anything mentioned there relevant when using std::string?

3) Below is my DLL code. The client code loads the DLL
dynamically and calls the Validate function. The Validate
function accepts the name of an internal function to call
and a std::string parameter specifying a file name that it
passes on to the internal function.
When I run this code the FileType1Test function generates
an exception and brings up the CPU window.

When debugging I can see that the input parameter "fileName"
contains a valid string when entering the function FileType1Test.
After the line "ifstream in..." the "fileName" content is ???? like
something corrupts the stack?

Thanks for any ideas,
Nick



#include <fstream>
using std::ifstream;
#include <string>
using std::string;

#pragma argsused
int WINAPI DllEntryPoint(HINSTANCE hinst,
unsigned long reason, void* lpReserved)
{
   return 1;
}

bool FileType1Test(const string& fileName)
{
   ifstream in(fileName.c_str());

   char c;
   in >> c;

   if(c == 'A')
      return true;
   else
      return false;
}


extern "C" __declspec(dllexport) string __stdcall Validate
(const string& funcName, const string& args)
{
   if(funcName == "FileType1Test")
      return FileType1Test(args) ? "TRUE" : "FALSE";
   else
      return "FALSE";
}