C / C++ / MFC

15-Jul-10 1:38

HI,
I have X.dll with some 2-3 functions.
I need to create another Y.dll which calls the X.dll functions.
I can import X.dll and its function and use in .exe
But i don't want to do that.
I need to know how to make it an .dll file with different function prototype.
Can anyone pls. help on this issue.

Richard MacCutchan15-Jul-10 2:05

15-Jul-10 2:05

The process is just the same as making X.dll, which probably used the functions of some other (Windows) dll. Just add the relevant header files to your source code and the X.lib to the link section of your build.

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viduran15-Jul-10 2:30

15-Jul-10 2:30

Do i need to call the load library function and Get procAddress in it to load the X.dll or not.
If so,I should have another function prototype which calls this dll's function and should return some value right?
I am confused in this.
can u giv any sample code link pls.
I am struggling on this

Richard MacCutchan15-Jul-10 2:52

Re: Nested DLL [modified]

15-Jul-10 2:52

induvijay wrote:
Do i need to call the load library function and Get procAddress in it to load the X.dll or not.

Well Karsten suggests (below) that you should, but it is really a matter of choice which method you use. Link and load or dynamic load.

If you are not using load library then, as I said before, you need to include the header for the X prototypes into your Y project. There is nothing really in this that is different to creating an EXE that uses the X.dll library; the difference is just the type of file created by the linker.

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viduran15-Jul-10 3:06

15-Jul-10 3:06

Hi,
I cant understand what u r saying.so pls go thru the code.
This is the code i wrote to create another dll.
Is it correct.
I dont know what mistake i have done here.
Pls.tell me what mistake i have done.
MultipleFn.DLL is my X.dll
The code i have given here is my Y.dll.This dll should call the function of X.dll.
Then i can create an .exe file which can call Y.dll.
The result should return the value by calling the function in X.dll from Y.dll.
I think now it will be clear.

#define DLLEXPORT __declspec(dllexport)
#define EXTERNC extern "C"

This is the function prototype i need to export from Y.dll

EXTERNC DLLEXPORT int Addition(int ,int);

typedef int *AddFunc1();
AddFunc1 _AddFunc;

This is my X.dll
HINSTANCE hInstLib = LoadLibrary("MultipleFn.dll");

int Addition(int a,int b)
{
if ( hInstLib != NULL )
{
FARPROC _AddFunc ;

_AddFunc = GetProcAddress ( hInstLib , "Add" ) ;

if ( _AddFunc != (FARPROC)NULL )
{
int c;
c = _AddFunc();
std::cout << "Loaded Successfully" << std::endl;
}
else
{
std::cout << "Failed to Load " << std::endl;
}

FreeLibrary ( hInstLib ) ;
}
return true;
}

modified on Thursday, July 15, 2010 9:14 AM

Richard MacCutchan15-Jul-10 4:18

15-Jul-10 4:18

induvijay wrote:
cant understand what u r saying.so pls go thru the code.

Nor me, please do not use txtspk but spell your words in full so people can understand you.

Also put your code between <pre></pre> tags so it shows in a readable format.

As to your code above, it seems a little confusing (why does X.dll try to load itself?); may I suggest you read through this article[^] to get a clearer understanding of building DLLs.

It's time for a new signature.

viduran15-Jul-10 19:39

15-Jul-10 19:39

Hi,
Thanks for your comments and reply.
the article is for calling dll in application.
I don't want that.I need to know how can i give reference for
dll in another dll.
I need to create two dll X and Y.
X.dll will have some functions exported.
Ex: double MyMathFuncs::Add(double a, double b);
Y.dll will have different function name but it should refer the function of X.dll.
Ex:double MyMathFuncs1::Addition(double a, double b);
This Addition function should call Add function in X.dll
then I will create an application which calls Addition function name
But i should get the result of Add in X.dll
Is it possible?
I think now it be clear for you that what i want to do.

Richard MacCutchan15-Jul-10 21:26

15-Jul-10 21:26

This is not at all difficult. Just create your X.dll in the normal way, then create your Y.dll in the normal way, with a reference to the function in X. Then create your application with a reference to Y. You can nest as deep as you like.

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viduran15-Jul-10 21:37

15-Jul-10 21:37

Hi,
Can you give any sample code that does this.
Because i am struggling with this for past 2 days and its very urgent.
one more How to give reference to my X.dll in Y.dll

Richard MacCutchan15-Jul-10 21:49

15-Jul-10 21:49

induvijay wrote:
Can you give any sample code that does this.

I gave you a reference yesterday; go and read the documentation which explains how to create a dll. As I keep saying it is exactly the same whether it has references to another dll or not.

induvijay wrote:
How to give reference to my X.dll in Y.dll

As I keep saying, the same way you would if it was an exe file.

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KarstenK15-Jul-10 2:26

KarstenK

15-Jul-10 2:26

it is better for that to use dynamic loading and accesing like that

typedef void (WINAPI *PGNSI)(LPSYSTEM_INFO);

PGNSI pGNSI = (PGNSI) GetProcAddress( GetModuleHandle(TEXT("kernel32.dll")), "GetNativeSystemInfo");

if(NULL != pGNSI)
{
pGNSI(&si);
return true;
}

Press F1 for help or google it.
Greetings from Germany

viduran15-Jul-10 2:55