Unhandled exception when call vc++ dll in vc++ code

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I want to call my vc++ dll in my vc++ code.
but the error occur that Unhandled exception at 0x00000000 in .exe: 0xC0000005: Access violation reading location 0x00000000.

after last line.I have call vc++ dll by ordinal no.

In .h file

C++

typedef int (*LPVAR)(char * ptr_f, char *CC);

In .cpp file

C++

HINSTANCE hDLL;
    	      hDLL = NULL;
    	LPVAR var;
    	hDLL = LoadLibrary("Prod.dll");
    	
    
    	if( hDLL == NULL )
    		AfxMessageBox("Could not load the DLL");

    	/*int ordinal = 2;
    	HMODULE  dll = LoadLibrary("Prod.dll");
    	FARPROC fn = GetProcAddress(dll, MAKEINTRESOURCE(ordinal));*/ //how to proceed after this.
    	
    	else
    	{
    		var = (LPVAR)GetProcAddress(hDLL, "Ver_C");
    		char *ch,a;
    		ch = (char*)malloc(100*sizeof(char));
    		
    		a = 'z'; 
    		int ans = var(ch,&a); //Unhandle exception after that.
    	}

Posted 19-Jul-12 1:40am

vikky08

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barneyman · Answer 1 · 2012-07-19T02:11:00

Solution 1

The docs for GetProcAddress[^] say it returns NULL if if fails

You're getting a NULL back (i worked that out from the exception) and you've got zero error handling in there

Posted 19-Jul-12 2:11am

barneyman

Albert Holguin · Answer 2 · 2012-07-19T09:00:00

Quote:
var = (LPVAR)GetProcAddress(hDLL, "Ver_C");

The "Ver_C" should match the name of your exported function exactly. Make sure you have a function named that, if you don't, that's your problem. If you do have a function named that, make sure it was a C-style export or else the name probably contains "name mangling".