Help Needed Using DLL

[varundua]

I have created a dll that has only one function in it and then i use that dll in a new project but the code is unable to locate the function in the dll

MouseHandle Dll

MouseHandle.h
#ifndef _MOUSE_HANDLE_H_
#define _MOUSE_HANDLE_H_
#include <windows.h>
#include <stdio.h>

extern "C" __declspec(dllexport) LRESULT CALLBACK MyMouseProc(int,WPARAM,LPARAM);

#endif

MouseHandle.cpp
#include "MouseHandle.h"


extern "C" __declspec(dllexport)
LRESULT CALLBACK MyMouseProc(int nCode,WPARAM wParam,LPARAM lParam) {
MessageBox(NULL,L"SUCCESS",L"ERROR",MB_ICONEXCLAMATION | MB_OK);
return 0;
}

Then i use this dll in my test project which doesn't works

#include <windows.h>
#include <stdio.h>

static HINSTANCE hinstDLL;
static HHOOK hhookSysMsg;


int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,LPSTR lpCmdLine, int nCmdShow){
HOOKPROC hkprcSysMsg;
hinstDLL = LoadLibrary(L"MouseHandle.dll");
if(hinstDLL == NULL)
errormessage();

hkprcSysMsg = NULL;
GetProcAddress(hinstDLL, L"MyMouseProc");
if(hkprcSysMsg == NULL)
errormessage();
return 0;
}

The program compiles well but on debuggin gives the error "The Specified Procedure cannot be found"
The Program is unable to find the procedure "MyMouseProc" in the dll

Have I done any error in making the dll ?

[Notsosuperhero]

GetProcAddress(hinstDLL, L"MyMouseProc");

You aren't assigning anything this. You need assign the function pointer.

hkprcSysMsg = (HOOKPROC)GetProcAddress(hinstDLL, L"MyMouseProc");

You just need to cast the GetProcAddress to whatever your function prototype is, you can define your own function pointers for this.
What you were doing is just loading the procedure but it wasn't stored anywhere. Now you call hkprcSysMsg like you would the DLL function itself.

[VladimirF]

GetProcAddress(hinstDLL, L"MyMouseProc");

Have I done any error in making the dll ?

How did you even compile that? GetProcAddress doesn't take pointer to a wide string.
To Notsosuperhero: although you are right, the cast you suggested won't help to fix OP's error "The Specified Procedure cannot be found".

[Cha0sBG]

either it's this

(HOOKPROC)

or hes using multi-byte character set.

[VladimirF]

either it's this

(HOOKPROC)

or hes using multi-byte character set.

Not sure what do you mean.
1. The (HOOKPROC) cast has nothing to do with the error.
2. Regardless of whether UNICODE was used or not, the GetProcAddress() function is only available in one flavor (unlike many other API function); it doesn’t take a wide string, and the prefix L in front of the text literal explicitly means: wide.

[Codeplug]

It does take a wide string under CE.

gg

[codecX]

use Depends.exe from "Microsoft Visual Studio 8\Common7\Tools\Bin" and check you dll to see if the name of your exported function is the same...

[VladimirF]

It does take a wide string under CE.

You are correct. I didn't know that. In my defence, if there would be any mention of WinCE - I would stay out of this thread.

[Igor Vartanov]

extern "C" __declspec(dllexport) LRESULT CALLBACK MyMouseProc(int,WPARAM,LPARAM);

. . .
The program compiles well but on debuggin gives the error "The Specified Procedure cannot be found"
The Program is unable to find the procedure "MyMouseProc" in the dll

With this declaration the exported name must be _MyMouseProc@12.

Besides, I cannot see any reason to resolve dll entry explicitly. Why don't you go with .lib?

[varundua]

GetProcAddress(hinstDLL, L"MyMouseProc");

You aren't assigning anything this. You need assign the function pointer.

hkprcSysMsg = (HOOKPROC)GetProcAddress(hinstDLL, L"MyMouseProc");

You just need to cast the GetProcAddress to whatever your function prototype is, you can define your own function pointers for this.
What you were doing is just loading the procedure but it wasn't stored anywhere. Now you call hkprcSysMsg like you would the DLL function itself.

I have tried this but doesn't helped , so i removed it but of no use.

[varundua]

I have made a slight change but it doesn't help

hkprcSysMsg = (HOOKPROC)GetProcAddress(hinstDLL, TEXT("_MyMouseProc@12"));
if(hkprcSysMsg == NULL)
	errormessage();

[varundua]

With this declaration the exported name must be _MyMouseProc@12.

Besides, I cannot see any reason to resolve dll entry explicitly. Why don't you go with .lib?

_MyMouseProc@12 doesn't works either. I am using the dynamic linking since i have to create a System Wide Mouse Hook to check mouse clicks on desktop.

[varundua]

use Depends.exe from "Microsoft Visual Studio 8\Common7\Tools\Bin" and check you dll to see if the name of your exported function is the same...

I used the tool it showed the function name as MyMouseProc. I still don't know what to do ??
I am attaching the result of the depend.exe with this reply

[Igor Vartanov]

I used the tool it showed the function name as MyMouseProc. I still don't know what to do ??

Say the truth is what to do. Either you miss (or cripple somehow) the CALLBACK modifier in your dll, or you use .def file that unmangles the exported name.

See my sample, and you see all works fine so far.

[Igor Vartanov]

You are correct. I didn't know that. In my defence, if there would be any mention of WinCE - I would stay out of this thread.

Vladimir, in your defence: there could not be a mention of WinCE, as there are no hooks in there.