Thread: Problem with mfc?

Hy,

i hope someone could help me

i have written an programm to controll an fpga card with an existing libary. The example programm was in c and i have to use c++ and the mfc for my project. I managed it to get rid of all error messages and the programm starts without any warnings but if i want to acess the dfpga board i get an Messagebox with the Error

unhandled exception in kartentestprog.exe: 0xC0000005: Access Violation.

Code:

void CKartentestprogDlg::OnStart() 
{
	// TODO: Add your control notification handler code here
	Sleep(1000);   
	fpga[0] = 1;  // <-- here comes the error
	fpga[1] = 0;
}

this is the inilization of the board wich works perfekt and all returns are ok.

Code:

int CKartentestprogDlg::OnCreate(LPCREATESTRUCT lpCreateStruct) 
{
	if (CDialog::OnCreate(lpCreateStruct) == -1)
		return -1;
	
	//connect the fpga and load the .hap file
	microenable   *board;
	fpga_design   *design;
	volatile unsigned long *fpga;
	int           rCode;
	int           PlxClk  = 40;
	int           FpgaClk = 100;
	char          DesignName[128] = "kartentester.hap";

	// -------------------------------------------------------------------
	// initialization of hardware
	// -------------------------------------------------------------------
	board = initialize_microenable();
	if (board==NULL) {
		//intf ("hardware initialization failed (code %d) : %s\n",
		//   Me_GetErrCode(NULL),Me_GetErrMsg(NULL));
		MessageBox( "Hardwareinizialisation failed", "Error", MB_OK );
		return -1;
	}
	//printf ("hardware initialization ok\n");
	MessageBox( "Hardware inizialisation is ok", "No Error", MB_OK );


	// -------------------------------------------------------------------
	// load a design
	// -------------------------------------------------------------------
	design  = load_design(board,DesignName);   // available in standard path
	if (design == NULL) {
		//printf ("load design %s failed (code %d) : %s\n",
		//	    DesignName,Me_GetErrCode(board),Me_GetErrMsg(board));
		MessageBox( "Load of the Design failed", "Error", MB_OK );
		return -1;
	}
	//printf ("load design ok\n");
	MessageBox( "Load of the Design is ok", "No Error", MB_OK );


	// -------------------------------------------------------------------
	// set clocks
	// -------------------------------------------------------------------
	rCode  = set_plx_clk (board,design, PlxClk);
	if (rCode) {
		//intf ("setting plx clock to %d Mhz failed:  error code %d)\n",PlxClk,rCode);
		MessageBox( "Clock Settings failed", "Error", MB_OK );
		return -1;
	}

	rCode  = set_fpga_clk (board,design, FpgaClk);
	if (rCode) {
		//printf ("setting fpga clock to %d Mhz failed: error code %d)\n",FpgaClk,rCode);
		MessageBox( "Clock Settings failed", "Error", MB_OK );
		return -1;
	}
	//printf ("clock setting ok (plx: %d Mhz, Fpga: %d Mhz)\n",PlxClk,FpgaClk);
	MessageBox( "Clock Settings are ok", "No Error", MB_OK );


	// -------------------------------------------------------------------
	// configure FPGA
	// -------------------------------------------------------------------
	rCode  = configure_fpga(board,design);
	if (rCode) {
		//printf ("configuration design %s failed: error code %d)\n",DesignName,rCode);
		MessageBox( "configuration design failed", "Error", MB_OK );
		return -1;
	}
	//printf ("configuration design %s ok\n",DesignName);
	MessageBox( "configuration design is ok", "No Error", MB_OK );


	// -------------------------------------------------------------------
	// get the access pointer
	// -------------------------------------------------------------------
	fpga  = (volatile unsigned long *) GetAccessPointer (board);
	if (fpga == NULL) {
		//printf ("memory map failed: error code %d (%s))\n",Me_GetErrCode(board),Me_GetErrMsg(board));
		MessageBox( "memory map failed", "Error", MB_OK );
		return -1;
	}
	MessageBox( "Memory Map ok", "No Error", MB_OK );


	
	return 0;
}

SO i hope someone could tell my what this error is all about and where it might come from.

Thanx for all answers

Greets Joerg

i thought it must have to do something with the declaration too, but i had tken the code most out of the example i hab for c.

in nearly an beginner with c++

Edit:

Thank you i marked the redefinition of the variable as an comment and now it works real fine