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DLL and Application

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kv79

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Re: DLL and Application

#21

Dec 21st, 2007

Hi,
when i ->include linking as
errors

Circular Untitled2 <- Untitled2.o dependency dropped.

Circular Untitled2 <- Untitled2.o dependency dropped.

When i turn off linking i get 3 more files ,
.dll, .lib, .a
And when i use my WIN API file who is some were above.Get no errors.BUT i did not see message box ,and it was ON included linking.

Last edited by kv79; Dec 21st, 2007 at 3:25 pm. Reason: And "Makefile "

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Re: DLL and Application

#22

Dec 21st, 2007

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Originally Posted by elite1986

Hi,
when i ->include linking as
errors

Circular Untitled2 <- Untitled2.o dependency dropped.

Circular Untitled2 <- Untitled2.o dependency dropped.

When i turn off linking i get 3 more files ,
.dll, .lib, .a
And when i use my WIN API file who is some were above.Get no errors.BUT i did not see message box ,and it was ON included linking.

Well I could not understand the errors. I don't know how do you add lib refreence in dev++. however you can use

#pragma comment(lib, "myfile.lib") in your cpp. It will autometicallty link the lib. After that you need not call the LoadLibrary. Just declare the prototype of function and call the function.

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Re: DLL and Application

#23

Dec 21st, 2007

Did you tried the impliementation I suggested earlier ? What is the error code ?

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Re: DLL and Application

#24

Dec 21st, 2007

Hi,

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
 
#include <windows.h>
#pragma comment(lib, "myfile.lib")
typedef void  (*function1_ptr) ();
function1_ptr function1=NULL;//Now create pointer and set its default value to NULL
 
 
int APIENTRY WinMain(HINSTANCE, HINSTANCE, LPSTR, int) { 
 
    HMODULE myDll = LoadLibrary("myfile.dll");
 
    if(myDll) {
        //obtain the function address
        function1 = (function1_ptr)GetProcAddress(myDll,"function1");  
    }  
 
    //use function where needed, but check before
    if(function1)
        function1();
 
    //finally free library
    FreeLibrary(myDll);
 
 
    return 0;
}
#include <windows.h>
#pragma comment(lib, "myfile.lib")
typedef void  (*function1_ptr) ();
function1_ptr function1=NULL;//Now create pointer and set its default value to NULL


int APIENTRY WinMain(HINSTANCE, HINSTANCE, LPSTR, int) { 
    
    HMODULE myDll = LoadLibrary("myfile.dll");
    
    if(myDll) {
        //obtain the function address
        function1 = (function1_ptr)GetProcAddress(myDll,"function1");  
    }  
    
    //use function where needed, but check before
    if(function1)
        function1();
        
    //finally free library
    FreeLibrary(myDll);
    
    
    return 0;
}

Had no errors and i have not seen message box

Last edited by kv79; Dec 21st, 2007 at 8:23 pm.

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Re: DLL and Application

#25

Dec 21st, 2007

I am now really confused ,
Were to go to understand these dll,
When i seen MSDN i understud 2 types but when i seen code it is really confusing.

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kv79

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Re: DLL and Application

#26

Dec 22nd, 2007

Hi,
I am really sorry it is my mistake.
It is working ,i get a message only when i put a
dll in same directory where is my exe and correct the names of .dll look up there code.

Thank you all for your effort for trying help me but basicly i needed to help my self.

But one or two more question 's what i do not understand.
1)When i writeing program in other language can i use dll or not?
2)It is his mistake or MSND

http://www.apitalk.com/document.php?id=1184209001_1
http://support.microsoft.com/kb/815065

Because he call this EXPLICITE and but msdn not.
3)MSND call load-time dyna... EXPLICIT
is it mind that run-time dyna... IMPLICIT?
4)When i use load-time is it mind when i load first time i do not need anymore dll?
5)Can i use any windows XP dll's?
6)What i need to do to attach another dll with this one?Do i need any other knowlage?
7)
if(function1)
function1();
Why the program won't work right without this ?
8)How to create different moduls in point of
runing faster programs.OR separate moduls.
9)I downloaded Visual C++ 2005 Expres Edition ,why i can't make a project ,what to do reslove that?

Last edited by kv79; Dec 22nd, 2007 at 1:16 pm.

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Re: DLL and Application

#27

Dec 22nd, 2007

>>I downloaded Visual C++ 2005 Expres Edition ,why i can't make a project ,what to do reslove that?

To create a project: select menu File -->New -->Project, then set Project Type to Win32 and Visual Studio Installed Templates to Win32 Console Application. At the bottom of the screen enter the project name and select the desired location. Finally on that window press the Ok button.

The next window to appear is the Application Settings window. Select Console Application and press the Finish button.

All done.

Last edited by Ancient Dragon; Dec 22nd, 2007 at 7:12 pm.

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Re: DLL and Application

#28

Dec 22nd, 2007

It's working but only when i put
in additional option ,empty project.

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Re: DLL and Application

#29

Dec 22nd, 2007

1)When i writeing program in other language can i use dll or not?
Yes, you can use a DLL in any language. The trick is only to match the correct "calling convention". Google it and read more about it. Most Windows DLLs have "stdcall" calling convention.

2)It is his mistake or MSND ... Because he call this EXPLICITE and but msdn not.
Both are correct. The difference between explicit and implicit linking is just whether or not the compiler links for you. For example, when writing windows programs, if you include <windows.h> then you can use all kinds of functions found in Windows DLLs without having to explicitly say which DLLs you want to use.

3)MSND call load-time dyna... EXPLICIT is it mind that run-time dyna... IMPLICIT?
This is non-sequitur. If you use LoadLibrary() then that is run-time loading. Otherwise it is load-time loading. This is a fairly simple, but technical issue. You shouldn't need worry about it.

The main interest for the programmer is that if a load-time DLL is not found, your program will not run. However, a run-time DLL (loaded with LoadLibrary()) allows you to choose whether to continue execution or not.

4)When i use load-time is it mind when i load first time i do not need anymore dll?
I don't understand your question.

5)Can i use any windows XP dll's?
Sure, why not?

6)What i need to do to attach another dll with this one?Do i need any other knowlage?
DLLs are separate things. One DLL may use another DLL, just as your EXE may use a DLL, but they are still separate, self-contained things.

7)
if(function1)
function1();
Why the program won't work right without this ?
It is possible that the DLL you loaded doesn't have the requested function. You must check to make sure that the function exists before you use it.

Keep in mind that you are really using a C shortcut here. "function1" is a pointer to a function. So first you test to see if the pointer is not NULL, and if not, then you call the function. To be absolutely explicitly correct it should read:
if (function1 != NULL) (*function1)();
C and C++ are nice and let you write it a shorter way:
if (function1) function1();

8)How to create different moduls in point of runing faster programs.OR separate moduls.
It makes no difference. (That is, if I understand your question correctly.)

Good luck!