C / C++ / MFC Discussion Boards

JaVinci18-May-05 22:27

18-May-05 22:27

Hi!

I'm trying to import a dll in Visual C++ 6. Can anybody help me?

When I link to that dll from another project it doesn't work. I'm sure I'm missing something, but I don't know what...

Here's how the dll is written (no errors, no warnings):

**************
* whatever.h *
**************

#ifdef __cplusplus
extern "C"{
#endif

class __declspec(dllexport) MyClass{
private:
char myString[100];
int myInteger;
public:
MyClass();
void getMyString(char * str);
int getMyInteger(void);
void setMyString(char * str);
void setMyInteger(int);
};

__declspec(dllexport) int function(MyClass * mc);

****************
* whatever.cpp *
****************

Just implementation here...

What can I do to import the class and the function from that dll (preferably not using a .def file)??? Please, help me, I'm going mad...
Cry | :((

Thank you!!!

Re: Problems with a dll

GDavy19-May-05 0:00

GDavy

19-May-05 0:00

when importing you need to declare __declspec(dllimport)

An often used method when writing dll^s is following:
in the header write a statement like

#ifdef __MY_DLL_PROJECT__
#define _DECSPEC_ __declspec(dllexport)
#else
#define _DECSPEC_ __declspec(dllimport)
#endif

all you need to do is define the symbol _MY_DLL_PROJECT_ in your dll project, and
define your class in the header as:

class _DECSPEC_ MyClass
{
...
};

Greetings,
Davy

Re: Problems with a dll

JaVinci19-May-05 3:50

JaVinci

19-May-05 3:50

Yeah, thanks...

I had already done that. I nearly kill myself when I realized that I wasn't setting the dependence between both projects. That was all I needed.

Thank you very much for your reply!!! Smile | :)

JaVinci

What is #pragma pack()?

xSoptik18-May-05 21:31

xSoptik

18-May-05 21:31

Hello all.
Can someone tell me in simple way what happen when I use preprocessor option #pragma pack ? I tryed it but I thing there is no effect.

Can you tell me what exactly happen?
Thank you a lot.

<br />
// sample code<br />
<br />
#pragma pack(1)   // turn byte alignment on ?????<br />
<br />
enum mENUM<br />
{<br />
   // an enum<br />
};<br />
struct p_mStruct<br />
{<br />
	UINT m_Ui;<br />
      // and so on<br />
};<br />
<br />
#pragma pack() // turn byte alignment off ?????<br />

Jaja Paja

Re: What is #pragma pack()?

Stlan18-May-05 22:06

Stlan

18-May-05 22:06

Perhaps a simple example is better than any explanation.
First case:

#pragma pack(1)<br />
struct MyStruct<br />
{<br />
BYTE a;<br />
UINT b;<br />
};<br />
#pragma pack()

sizeof(struct MyStruct) will return 5 bytes (1+4=5)

Second case:

#pragma pack(4)<br />
struct MyStruct<br />
{<br />
BYTE a;<br />
UINT b;<br />
};<br />
#pragma pack()

sizeof(struct MyStruct) will now return 8 bytes! (1+3+4=8) because the compiler aligns each member of MyStruct to a 4 bytes boundary. Concretly, the directive tells the compiler that the address of each member must be divisible by 4. To do that, the compiler insert the necessary blank bytes between variable members.

Re: What is #pragma pack()?

xSoptik19-May-05 1:14

xSoptik

19-May-05 1:14

Ok.
I understand now. Thank you a lot.
xSoptik

Grid controls with sliders and spin controls

surfdabbler18-May-05 21:15

surfdabbler

18-May-05 21:15

Anyone know if the Ultimate Grid is included in the Ultimate Toolbox? The website has no contact information, and the only way I can see to purchase these products is through codeproject... Unsure | :~

Chris Maunder's DataGrid is great, but I just don't have the time to implement slider controls and spin boxes. If anyone knows of good implementations of these, let me know. (The GridTreeCtrl has a spin box cell class in it, but it doesn't seem to work very well without the ability to hold down the spin control, and frequent double-count for a single click of the buttons.)

Communication

usmanmir18-May-05 20:43

usmanmir

18-May-05 20:43

I want to a program in vc 6 by using which i can send message say "HELLO" to all the active users on internet.
Can any one guide me or refer me to a good site or refer or provide me some useful links or direct or provide me some source code in vc 6 of the above stated problem.