Compiles, but Freezes up

[jamez05]

I'm using Visual Studio 2005

I have a function named "CallBIOWDLL" that calls a third party dll. When I compile and run the program at this point, it works fine. However, When I call CallBIOWDLL from my main function, it compiles, but when I run the program it freezes. I'm working with a simple win32 console program. Below is the code and debugging information. I've been struggling with this for a long time so any help is greatly appreciated:

// test5.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include <windows.h>

#define MAXLEN 360

char Details[12000];
char ErrMess[1200];
char numLines[12];


char EstLin[15];
char EstNon[15];
char EstUlt[15];
char EstPrim[15];
char EstMitiLin[15];
char EstMitiNon[15];
char UltTime[30];
char PrimTime[30];

char szString[MAXLEN] ;

int CallBIOWDLL(void)
{ 
    
	strcpy(szString,"O=C");
	/* get handle to dll */
     HINSTANCE hGetProcIDDLL = LoadLibrary("C:\\WINDOWS\\system32\\BIOWDLL.dll");

     /* get pointer to the function in the dll*/
     FARPROC lpfnGetProcessID = GetProcAddress(HMODULE(hGetProcIDDLL), "GetSrcBIOWIN");

     /* Define the Function in the DLL for reuse. This is just prototyping
        the dll's function. A mock of it. Use "stdcall" for maximum compatibility.
 */   
     typedef int (__stdcall * pICFUNC)(char*,char*,char*);

     pICFUNC MyFunction;
     MyFunction = pICFUNC(lpfnGetProcessID);


	 /* The actual call to the function contained in the dll */ 
     int intMyReturnVal = MyFunction(szString,"test2",EstLin);

     /* Release the Dll */
     FreeLibrary(hGetProcIDDLL);

     /* The return val from the dll */
     return intMyReturnVal;
}


int _tmain(int argc, _TCHAR* argv[])
{
	CallBIOWDLL();
	return 0;
}

Debugging info:

'test5.exe': Loaded 'C:\Documents and Settings\epajn\My Documents\Visual Studio 2005\Projects\test5\Debug\test5.exe', Symbols loaded.
'test5.exe': Loaded 'C:\WINDOWS\system32\ntdll.dll', No symbols loaded.
'test5.exe': Loaded 'C:\WINDOWS\system32\kernel32.dll', No symbols loaded.
'test5.exe': Loaded 'C:\WINDOWS\WinSxS\x86_Microsoft.VC80.DebugCRT_1fc8b3b9a1e18e3b_8.0.50727.42_x-ww_f75eb16c\msvcr80d.dll', Symbols loaded.
'test5.exe': Loaded 'C:\WINDOWS\system32\msvcrt.dll', No symbols loaded.
'test5.exe': Loaded 'C:\WINDOWS\system32\BIOWDLL.dll', Binary was not built with debug information.
'test5.exe': Loaded 'C:\WINDOWS\system32\version.dll', No symbols loaded.
'test5.exe': Loaded 'C:\WINDOWS\system32\advapi32.dll', No symbols loaded.
'test5.exe': Loaded 'C:\WINDOWS\system32\rpcrt4.dll', No symbols loaded.
'test5.exe': Loaded 'C:\WINDOWS\system32\user32.dll', No symbols loaded.
'test5.exe': Loaded 'C:\WINDOWS\system32\gdi32.dll', No symbols loaded.
'test5.exe': Loaded 'C:\WINDOWS\system32\shlwapi.dll', No symbols loaded.
'test5.exe': Loaded 'C:\WINDOWS\system32\imm32.dll', No symbols loaded.
'test5.exe': Loaded 'C:\WINDOWS\system32\lpk.dll', No symbols loaded.
'test5.exe': Loaded 'C:\WINDOWS\system32\usp10.dll', No symbols loaded.
'test5.exe': Loaded 'C:\WINDOWS\system32\apphelp.dll', No symbols loaded.
The thread 'Win32 Thread' (0xd24) has exited with code 0 (0x0).
Unhandled exception at 0x00000000 in test5.exe: 0xC0000005: Access violation reading location 0x00000000.
First-chance exception at 0x00000000 in test5.exe: 0xC0000005: Access violation reading location 0x00000000.
Unhandled exception at 0x00000000 in test5.exe: 0xC0000005: Access violation reading location 0x00000000.
First-chance exception at 0x00000000 in test5.exe: 0xC0000005: Access violation reading location 0x00000000.
Unhandled exception at 0x00000000 in test5.exe: 0xC0000005: Access violation reading location 0x00000000.
First-chance exception at 0x00000000 in test5.exe: 0xC0000005: Access violation reading location 0x00000000.
Unhandled exception at 0x00000000 in test5.exe: 0xC0000005: Access violation reading location 0x00000000.
First-chance exception at 0x00000000 in test5.exe: 0xC0000005: Access violation reading location 0x00000000.
Unhandled exception at 0x00000000 in test5.exe: 0xC0000005: Access violation reading location 0x00000000.
First-chance exception at 0x00000000 in test5.exe: 0xC0000005: Access violation reading location 0x00000000.
Unhandled exception at 0x00000000 in test5.exe: 0xC0000005: Access violation reading location 0x00000000.
The program '[3852] test5.exe: Native' has exited with code 0 (0x0).

 

[Salem]

> HINSTANCE hGetProcIDDLL = LoadLibrary("C:\\WINDOWS\\system32\\BIOWDLL.dll");
> FARPROC lpfnGetProcessID = GetProcAddress(HMODULE(hGetProcIDDLL), "GetSrcBIOWIN");
You could at least check for success, before you go off potentially using NULL as a function pointer.


--

 

[jamez05]

What do you mean by check for success? I need to take a class or read a good book. However, I did figure out how to call the dll implicitly in a windows program I've written in C. When I convert it to C++ though, it errors out. It has something to do with the character type. Do you have any advice? Below is the code:

#include <windows.h>

__declspec ( dllexport )int WINAPI GetSrcBIOWIN (PSTR cSmilePass,
   PSTR cChemical, PSTR EstLin, PSTR EstNon, PSTR EstUlt, PSTR EstPrim,
   PSTR UltTime, PSTR PrimTime, PSTR EstMitiLin, PSTR EstMitiNon,
   PSTR DetailResults, PSTR numLines, PSTR ErrorMess);


#define MAXLEN 360

char Details[12000];
char ErrMess[1200];
char numLines[12];

char EstLin[15];
char EstNon[15];
char EstUlt[15];
char EstPrim[15];
char EstMitiLin[15];
char EstMitiNon[15];
char UltTime[30];
char PrimTime[30];



int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, 
    PSTR szCmdLine, int nCmdShow)
{
   char szBuffer[MAXLEN] ;

	int Ret1 = GetSrcBIOWIN("O=C","ChemName",
               EstLin,EstNon,EstUlt,EstPrim,
               UltTime,PrimTime,EstMitiLin,EstMitiNon,
               Details,numLines,ErrMess);	

    sprintf(szBuffer,"Linear: %s  NonLinear: %s  Ult: %s  Prim: %s  Miti: %s  NonMiti: %s",
          EstLin,EstNon,EstUlt,EstPrim,EstMitiLin,EstMitiNon);

	
	MessageBox(NULL, szBuffer, "Note", MB_OK);
    return 0;
}

 

[jamez05]

Figured it out.

Added extern "C" in front of _declspec