Calling a Dll

Hello!
I made a dll :

PHP Code:

---

#include "MYDLL.h"
__declspec( dllexport ) int doubleInt(int iNumber)
{
    return (iNumber * 2);
} 


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and a .DEF

Code:

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LIBRARY        MYDLL
  DESCRIPTION    "Simply double an integer"
  EXPORTS
            doubleInt  @1

---

but now that's what I just found in some thread here but that doesn't work and I know that I miss something but I really do not have a clue how to call my DLL in an other C++ project :(

Here is what I got :

PHP Code:

---

#include <iostream>

//Prototype
void LoadDll(void);

void main(void)
{
    LoadDll();
}//End main

void LoadDll(void)
{
    HMODULE hDLL = LoadLibrary("MYDLL");
    if (hDLL)
        MYFUNC function = (MYFUNC)GetProcAddress(hDLL, "MyFunction");
    else
        std::cout << "Error loading DLL";
}//End LoadDll 


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Any one can help me ?

Here is all error :

Code:

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error C2065: 'HMODULE' : undeclared identifier

error C2146: syntax error : missing ';' before identifier 'hDLL'

error C2065: 'hDLL' : undeclared identifier

error C2065: 'LoadLibrary' : undeclared identifier

error C2065: 'MYFUNC' : undeclared identifier

error C2146: syntax error : missing ';' before identifier 'function'

error C2065: 'function' : undeclared identifier

error C2146: syntax error : missing ';' before identifier 'GetProcAddress'

error C2065: 'GetProcAddress' : undeclared identifier

error C2181: illegal else without matching if

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Try this...

Your DLL source file:

PHP Code:

---

#include "MYDLL.h"
int __declspec( dllexport ) doubleInt(int iNumber)
{
    return (iNumber * 2);
} 


---

Your .DEF file:

PHP Code:

---

LIBRARY        "MYDLL.dll"
   DESCRIPTION    "Simply double an integer"
   EXPORTS
            doubleInt 


---

Almost make sure your DLL header file is also right.

Now, the code you're testing your DLL with:

PHP Code:

---

#include <iostream>
#include <windows.h> 'Must if you're using LoadLibrary, etc
//Prototype
void LoadDll(void);
//Must declare a function pointer type you want
typedef void (*MYFUNCTION)(int);
void main(void)
{
    LoadDll();
}//End main

void LoadDll(void)
{
'HMODULE is old.  Use HINSTANCE instead
    HINSTANCE hDLL = LoadLibrary("MYDLL.dll"); 'Extension
    if (hDLL)
      MYFUNCTION myfunc= (MYFUNCTION)GetProcAddress(hDLL, "MyFunction"); //Shouldn't it be doubleInt?
//You can free the DLL here just for performance
//FreeLibrary(hDLL);
    else
        std::cout << "Error loading DLL";
}//End LoadDll 


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Make sure the path to DLL is correct and naming of all the files is also correct.
Might be some typos in the above code though.

Yes but how can i use the doubleInt function ?

I tryed that in the main :

PHP Code:

---

void main(void)
{
    LoadDll();
    int a = 5;
    a = myfunc(a);
    std::cout << a;
}//End main 


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but that doesn't work

You have to assign it to a function pointer, then call through the pointer:

Code:

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(*myfunc)(a);

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Why that doesn't work ?

PHP Code:

---

#include <iostream>
#include <windows.h> //Must if you're using LoadLibrary, etc
//Prototype
void LoadDll(void);
//Must declare a function pointer type you want
typedef int (*MYFUNCTION)(int);
void main(void)
{
    LoadDll();
    int a = 5;
    a = (*myfunc)(a);
    std::cout << a;
}//End main

void LoadDll(void)
{
    HINSTANCE hDLL = LoadLibrary("deuxDll.dll");
    if (hDLL)
      MYFUNCTION myfunc = (MYFUNCTION)GetProcAddress(hDLL, "doubleInt");
//You can free the DLL here just for performance
//FreeLibrary(hDLL);
    else
        std::cout << "Error loading DLL";
}//End LoadDll 


---

Error:

Code:

---

error C2065: 'myfunc' : undeclared identifier

error C2100: illegal indirection

---

Declare "myfunc" on the top of your code.

PHP Code:

---

#include <iostream>
#include <windows.h> //Must if you're using LoadLibrary, etc
//Prototype
void LoadDll(void);
//Must declare a function pointer type you want
typedef int (*MYFUNCTION)(int);
MYFUNCTION myfunc; //Declare it
void main(void)
{
    LoadDll();
    int a = 5;
    a = (*myfunc)(a);
    std::cout << a;
}//End main

void LoadDll(void)
{
    HINSTANCE hDLL = LoadLibrary("deuxDll.dll");
    if (hDLL)
      myfunc = (MYFUNCTION)GetProcAddress(hDLL, "doubleInt");
//You can free the DLL here just for performance
//FreeLibrary(hDLL);
    else
        std::cout << "Error loading DLL";
}//End LoadDll 


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Ok but I have a speacial msgbox with an error when I execute, maybe I have an error when is time to load the DLL in the pointer.

...thx for debugging me I appreciate.

When I pass the program in debug I have RED hex code in the debugger screen... I think I do something wrong :(

Ok I found out what was wrong :):):) THX all!!!!

Quote:

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Originally posted by DaoK
When I pass the program in debug I have RED hex code in the debugger screen... I think I do something wrong :(

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It's highlighted in red if the value's changed :)


Everything working now?