#define to static const int

[TFobear]

I have my ideas of scope messed up.

I have a native DLL which I am compiling with /CLR in hopes to export Native global functions and constants. To do so I have created a class I am hoping I can call from C# or VB.Net clients statically.. so:

namespace CompanyNameManaged {

public ref struct CompanyName sealed abstract
{
    
static void func1(String^ filename, int page); //called from c# like CompanyName.func1("literal", 9);

// These are #defined in a seperate, unmanaged file
ref struct CONSTANTS sealed abstract
{
        
//From Native Header: #define DEF01 0x0001
const int DEF01 = 0x0001; //doesnt compile, needs to be "Static"
static const int DEF02 = 0x0002; //works, called from DLL as CompanyName.CONSTANTS.DEF02;
static const int DEF03 = 0x0003; 
//DEF03 is defined in windows api file "WinGdi.h" I dont believe I am including this file anywhere 
//but I believe this is the source of my problem since when I change name (MY_DEF03) it compiles.

}; //ref stuct CONSTANTS

}; //ref struct CompanyName

}; //namespace

SO, when I try to compile with the const "DEF03" I have issues, the error is:
error C2059: syntax error : 'constant'
error C2238: unexpected token(s) preceding ';'

It shouldnt have an issue because I think the scope is "CompanyName::CONSTANTS:EF03"

Should I be declaring the wrapper classes differently? The purpose here is to expose native code to the client.

Thanks in advanced.

[cilu]

You just want a class with a bunch of constants? You could make it static instead of sealed abstract.

   static ref struct CONSTANTS 
   {
      const int DEF01;
      const int DEF02;
      const int DEF03;

      CONSTANTS():DEF01(0x0001), DEF02(0x0002), DEF03(0x0003)
      {}
   };

[TFobear]

I like this solution, in my honest oppinion sealed and abstract are just syntatic sugar I dont really need. Any ways, this doesnt solve my problem though, as the compiler is still seeing them as redefinitions of #define constants.

As this is a native dll that uses these #defines in numerous places, I would like to leave the existing code untouched. However it would be nice to be able to export these definitions to a managed client.

I think what my solution could be... though it seems like a hack to me... is this:

//NativeDecl.h

void func1(void);
void func2(void);

#ifndef MANAGED_DECL
   #define CONST1 0x0001
   #define CONST2 0x0002
#endif

//ManagedDecl.h

#define MANAGED_DECL
#include "NativeDecl.h"

static ref struct Foo { const int CONST1, CONST2 };

*edit* That is not a valid solution, the consts generating the errors ("PHYSICALWIDTH" and "PHYSICALHEIGHT") are also defined in WinGdi.h ...

[Alex F]

Macro problem cannot be solved by namespaces. Just undef this macro:

#undef DEF03
...
ref struct CONSTANTS sealed abstract
...
static const int DEF03 = 0x0003;

[TFobear]

thanks Alex, I have done this and am moving on.

However, the suggestion to make the class static rather than sealed abstract - produces error c2597 "illegal reference to non-static member"

example:

public ref struct Toolkit sealed abstract
{
   static ref struct Module1
   {
      static ref struct Constants
      {
         const int DEF1;
         Constants() : DEF1(0x1010) { }
      };

   };

   static ref struct Module2
   {
      void func1(IntPtr x);
   };
};

void Toolkit::Module2::func1(IntPtr x)
{
   OtherFunc( x, Module1::Constants::DEF1 ); //error c2597
}

MSDN's example shows totally different situation. http://msdn.microsoft.com/en-us/libr...a2(VS.71).aspx

[Alex F]

Use "literal" keyword:

literal int DEF1 = 0x1010;

This is the same as

const int DEF1 = 0x1010;

in C#.

[TFobear]

Thanks yet again!!

... thats funky, i guess they needed a way to differentiate native const types and managed ones.

I am, as you can tell, a C++/Cli newbie. I have found a great *eBook* though that delves into specifics, including questions I have been having about DllMain and inititialization issues.

http://int6.net/ebook/Expert.Cpp.Cli.NET.pdf

[mani3355]

hi,


i guess they needed a way to differentiate native const types and managed ones.


regards,
phe9oxis,
http://www.guidebuddha.com