C / C++ / MFC

Re: Setting Font and Text Colors items of ComboBox Solved almost

22-May-22 12:32

At first I thought I could set the above values in DrawItem (I have an ownerdraw combobox). The Drawitem however only gets invoked when clicking the right icon after the display

I have tried OnCtlColor in the dialog (for the text color) It does get invoked but doesnt set the text color.

Tried OnCreate in ComboBox for the font for that it just didn't get invoked

Thanks

ForNow22-May-22 13:28

Re: Setting Font and Text Colors items of ComboBox Solved almost

22-May-22 13:28

Presubclasswindntrolow got the font working

Then I re-read remarks on CTLCOLOR seems like for a combobox the message is sent to the combobox as it is the parent to the edit control and list box

However the ctlcolor for the combobox only got called twice and both times had a value CTLCOLOREDIT

maybe the idea is then to set the color of the listbox in the Drawitem

Thanks

Victor Nijegorodov22-May-22 20:14

Re: Setting Font and Text Colors items of ComboBox Solved almost

22-May-22 20:14

I gave yu a link to a CP article: Re: OwnerDraw Combox - C / C++ / MFC Discussion Boards
Did you look at it?

ForNow22-May-22 22:26

Accessing and displaying semaphore count

22-May-22 22:26

I downloaded it built it debug x64 and as I was stepping thru that code it got an exception it was somewhere in MFC code the call stack indicated it was from an Additem Ill go back and try to fix it up thank you

coco24322-May-22 1:42

22-May-22 1:42

Hi,

In my trying on understanding semaphores I am looking on the following example:

C++

DWORD WINAPI ChildThreadProc( HWND hWnd )
{
	TCHAR szBuffer[256];          // buffer
	DWORD dwSemCount = 0;         // printing semaphore count
	HANDLE hSemaphore = OpenSemaphore( SYNCHRONIZE, FALSE, "TEST SEMAPHORE");
	wsprintf(szBuffer, "Thread %x waiting for semaphore %x", GetCurrentThreadId(), hSemaphore );
	SendMessage(hWnd, WM_USER, 0, (LPARAM)szBuffer);
	// Check for signaled semaphore
	WaitForSingleObject( hSemaphore, INFINITE );
	wsprintf(szBuffer, "Thread %x got semaphore", GetCurrentThreadId() );
	SendMessage(hWnd, WM_USER, 0, (LPARAM)szBuffer);
	Sleep(5000);
	//dwSCount = dwSemCount;
	//Release semaphore
	ReleaseSemaphore( hSemaphore, 1, (LPLONG)&dwSCount );
	wsprintf( szBuffer, "Thread %x is done with semaphore. Its count was %ld.", GetCurrentThreadId(), dwSemCount );
	SendMessage( hWnd, WM_USER, 0, (LPARAM)szBuffer );
	CloseHandle( hSemaphore );
	ExitThread ( TRUE );
}

And I am having 2 problems here:

-first, the dwSemCount value si always printed as 0, even if the semaphore works fine
-second, incrementing the counter with ReleaseSemaphore function from inside of thread doesn't working, I can't explain why.

Can you please help me with some advices?

Thank you very much,

Mircea Neacsu22-May-22 2:02

Mircea Neacsu

22-May-22 2:02

Thread doesn’t have enough access rights to semaphore. It would need SEMAPHORE_MODIFY_STATE. See Synchronization Object Security and Access Rights - Win32 apps | Microsoft Docs[^]

Checking return value of ReleaseSemaphore would show that it fails.

Mircea

coco24322-May-22 2:48

22-May-22 2:48

Thank you Mircea,

I had changed the access rights for OpenSemaphore and the ReleaseSemaphore is working now.

Please help me and with the displaying of the semaphore counter:

C++

ReleaseSemaphore( hSemaphore, 1, (LPLONG)&dwSCount );
wsprintf( szBuffer, "Thread %x is done with semaphore. Its count was %ld.", GetCurrentThreadId(), dwSemCount );
SendMessage( hWnd, WM_USER, 0, (LPARAM)szBuffer );

The displayed value of the dwSemCount is always 0, but it should be equal with the initial value, or with the decremented value, where is the mistake or where I am wrong?

Thank you,

Mircea Neacsu22-May-22 2:51

Mircea Neacsu

22-May-22 2:51

Hmm, dwSCount vs dwSemCount. Could that be a typo?

Mircea

Richard Andrew x6422-May-22 3:04

Richard Andrew x64

22-May-22 3:04

Good catch!

The difficult we do right away...
...the impossible takes slightly longer.

coco24322-May-22 5:07

22-May-22 5:07

Sorry,

I made some test with SCount as global variable because of the problems, but yes, I had replaced this variable
and is ok now.

Thank you very much,

Victor Nijegorodov22-May-22 6:15

22-May-22 6:15

You should avoid using SendMessage form a worker to a main thread. It could lead to a deadlock. In most cases PostMessage is more preferable.

coco24322-May-22 7:17

22-May-22 7:17

Noted,

Thank you,

OwnerDraw Combox

ForNow18-May-22 14:28

18-May-22 14:28

Hi
with the combobox it seems that drawitem function is only called after I click the icon of drop down.

My combobox displays with the first entry in the editbox (unformatted i.e. font and color).

Is there any to have drawitem invoked before it displays as I would like to format the entry in the edit control

Thanks

Re: OwnerDraw Combox

Victor Nijegorodov18-May-22 21:13

18-May-22 21:13

Perhaps your implementation/override of DrawItem is not complete?
Have a look at some of the CP articles describing the ownerdraw comboboxe, like this one:
Group Combo Box

C++ code for Gomoku

Lesego Molelekoa18-May-22 5:58

Lesego Molelekoa

18-May-22 5:58

Hi . Recently i've got to make a game called gomoku between two players and I don't know where to start. Could you please assist with the steps or at least a C++ code for the Gomoku game with comments so that I can at least be able to follow what has been coded.

Re: C++ code for Gomoku

Richard MacCutchan18-May-22 6:01

Richard MacCutchan

18-May-22 6:01

The first thing you need to do is to study the game so you understand the rules. You can then start to figure out what each step of the game can do. From that you should be able to create a basic design document. Until you have done all that there is no point in thinking about actual code.

Re: C++ code for Gomoku

Victor Nijegorodov18-May-22 9:25

Security Check Stack overflow compiler GS option

18-May-22 9:25

Did you try something from Gomoku game code - Google Search

ForNow16-May-22 2:16

Re: Security Check Stack overflow compiler GS option

16-May-22 2:16

Hi
I put my ownerdraw code in a C dll upon exiting it I got a Security check stack overflow. I turned the /GS complier option off looked to work fine under VS debugger. The Calling code is MFC C/C++

The DLL is in C

Here is the MFC code

C++

CMystatic::CMystatic()
{
    width = 0;
    mod = LoadLibrary(TEXT("C:\\SYSADATA\\SYSADATA\\x64\\Debug\\SYSADATA.DLL"));
    drawptr = (fownerdraw)GetProcAddress(mod, "ownerdraw");
    strsize.cx = 0;
    strsize.cy = 0;
    myexitparm = &exitparm;
}

void CMystatic::DrawItem(LPDRAWITEMSTRUCT pdi)
{
    
    exitparm.pdi = pdi;
    exitparm.sizeptr = &strsize;
    
    (drawptr)(myexitparm);
    
}

Here is the C DLL

C++

 typedef struct EXITPARM
{
    LPDRAWITEMSTRUCT pdi;
    SIZE* sizeptr;

};
// void  ownerdraw(exitparmptr);
typedef struct EXITPARM* exitparmptr;
__declspec(dllexport) void ownerdraw(exitparmptr parmptr);

void  ownerdraw(exitparmptr parmptr)
{
    
    LPDRAWITEMSTRUCT pdi = parmptr->pdi;
   // (char*)myexit += 8;
    SIZE* mysize = parmptr->sizeptr;

Victor Nijegorodov16-May-22 3:08

Re: Security Check Stack overflow compiler GS option

16-May-22 3:08

I never saw such an error/warning in my code.
What I see in your code snippet (and it is was I don't like) is this expression:

C++

void  ownerdraw(exitparmptr parmptr)
{ 
    LPDRAWITEMSTRUCT pdi = parmptr->pdi;

What happens when the function argument parmptr is nullptr? Yes, the program crash!

ForNow16-May-22 3:22