[boost] boost::bind GetProcAddress

From: Steven Ketcham (sketcham_at_[hidden])
Date: 2003-04-22 15:00:56

Experimenting with boost::bind and boost::function using Window's
GetProcAddress(...) function. I don't really see an advantage of boost over
the regualar function pointer in this case. Is there a better way to do the
boost version?

Thanks!

/// DllFunction: int __stdcall DllFunction(int param);

//sample  1
#define BOOST_FUNCTION_NO_DEPRECATED
#define BOOST_BIND_ENABLE_STDCALL

#include "./boost/function.hpp"
#include "./boost/bind.hpp"

void MyClass::DoTest1()
{
   MyLoadLibrary myLoadLibrary( "MyDll.dll" );
   if ( myLoadLibrary.IsOpen() == true )
   {
      //sample function - bFunction is the typedef name
      typedef boost::function1<int, int> bFunction;

      bFunction f = boost::bind(reinterpret_cast< int
(*)(int)>(myLoadLibrary.GetFunction("DllFunction")), _1);

      //overloaded() is called
      if ( f )
      {
         int param = 0;
         int result = f(param);
      }
   }
}

//sample2
void MyClass::DoTest2()
{
   MyLoadLibrary myLoadLibrary( "MyDll.dll" );
   if ( myLoadLibrary.IsOpen() == true )
   {
      //sample function - pFunction is the typedef name
      typedef int (__stdcall *pFunction)(int);

      pDsiGrab f = NULL;
      f =
reinterpret_cast<pDsiGrab>(myLoadLibrary.GetFunction("DllFunction"));

      if ( f != NULL )
      {
         int param = 0;
         //dereference pointer
         int result = (*f)(param);
      }
   }
}

class MyLoadLibrary
{
private:
   HINSTANCE f_hDLL;               // Handle to DLL

public:
   MyLoadLibrary()
   {
   }

   ~MyLoadLibrary()
   {
      this->Close();
   }

   void Close()
   {
      if ( f_hDLL != NULL )
      {
         FreeLibrary(f_hDLL);
      }
   }

   bool Open(const std::string & dllName)
   {
      this->Close();
      f_hDLL = LoadLibrary(dllName.c_str());

      return (f_hDLL != NULL);
   }

   bool IsOpen() const
   {
      return (f_hDLL != NULL);
   }

   FARPROC GetFunction(const std::string & functionName)
   {
      FARPROC r = NULL;
      if ( f_hDLL != NULL )
      {
         r = GetProcAddress(f_hDLL, functionName.c_str());
      }

      return r;
   }
};