C / C++ / MFC

Re: Thread blocking interface

4-Jun-02 6:48

Calling Sleep() in worker should have no effect on main thread. Unless you're waiting for worker to finish...

Tomasz Sowinski -- http://www.shooltz.com

- It's for protection
- Protection from what? Zee Germans?

Hans Ruck4-Jun-02 7:09

Hans Ruck

4-Jun-02 7:09

It's strange, because i use a mutex - working excellent even in such conditions - to synchronize the access to some data located in an object belonging to another thread, but not the main-one.
Indeed, it seems that the delay comes from this mutex and hard times are to come. Cry | :((

Anyway, thanx!

rechi

Single document in MDI

Haakon S.4-Jun-02 6:14

4-Jun-02 6:14

I have an application with many different views, but I want to have only a single document open for a process. How can I best block OnFileOpen() and OnFileNew()?

1. I have tried OnUpdate in my CMainFrame by using CCmdUI. Can't make it work.

2. I override the OnFileOpen() and OnFileNew() to check if a document is already active. But if I use

CDocument* pDoc=((CFrameWnd*)m_pMainWnd)->GetActiveDocument();

I always get a NULL pointer ?? WTF | :WTF:

Regards, Haakon S.

Tomasz Sowinski4-Jun-02 6:13

4-Jun-02 6:13

Haakon S. wrote:
How can I best block OnFileOpen() and OnFileNew()?

I'm not sure why do you want to block. Just close open document and create/open another.

Haakon S. wrote:
I always get a NULL pointer ??

CWinApp::CloseAllDocuments does what name suggests.

I'd override CWinApp::OpenDocumentFile (which is also called for new docs) to close everything before new doc is open/created.

Tomasz Sowinski -- http://www.shooltz.com

- It's for protection
- Protection from what? Zee Germans?

Haakon S.4-Jun-02 6:26

4-Jun-02 6:26

I don't want anybody to have several documents open at the same time (in the same process), which you can normally do in a MDI apllication. I want to disable this functionality.

Haakon S.

Tomasz Sowinski4-Jun-02 6:27

4-Jun-02 6:27

I know what you want to do. I just think that instead of blocking File/New and File/Open you should close current document and load/create new one. This will result in at most one document open in any given moment.

Tomasz Sowinski -- http://www.shooltz.com

- It's for protection
- Protection from what? Zee Germans?

Haakon S.4-Jun-02 7:38

4-Jun-02 7:38

What you are saying is the right thing to do. You know it and I know it. But what about the next man? It should be possible to totally rule out the option.

There are several reasons, by the way. First, if you have many different views it gets totally messed up if you have several documents. Secondly, my app. will probably break with several documents (probably poor programming, but anyway... Blush | :O

).

So, once again, help in this matter will be greatly appreciated.

Haakon S.

Tomasz Sowinski4-Jun-02 23:32

4-Jun-02 23:32

My solution (close open document before opening/creating new one) gives you exactly what you need: you have MDI app --and-- at most one document is open. Your app will not break; user will be working with exactly one document.

Tomasz Sowinski -- http://www.shooltz.com

- It's for protection
- Protection from what? Zee Germans?

Ed Gadziemski4-Jun-02 14:52

Ed Gadziemski

4-Jun-02 14:52

CMDIFrameWnd *pFrame =
(CMDIFrameWnd*)AfxGetApp()->m_pMainWnd;

CMDIChildWnd *pChild = pFrame->MDIGetActive();

Edit box with units

Ali Asi4-Jun-02 5:56

Ali Asi

4-Jun-02 5:56

Description:
============
There are a lot of times in a dialog box that one would want to read-in/display a number that has a unit. For instance, this can be achieved by a pair of edit box and static box.

Edit box control containing the value Static Control displaying the unit:
2.378e-3 Meter

User can also choose his favorite unit system in a centralized dialog box. For example, he could specify whether he would rather to have the lengths to be displayed in Meter, Inch, Centimeter, ...

Question:
=========
I thought the best way to accomplish this task is deriving a customized edit box and static controls from MFC's CEdit and CStatic classes and adding the following paramteres to it:

double m_Conversion; // Conversion factor from SI to the user's selected unit.
CString m_UnitName; // The Unit's name, "m", "cm", "mm", ...

This seems to be such a common problem that I thought there might have already been some specialized codes written by other people for this purpose.

I appreciate any input/suggestion/pointers in regards to my question. Please e-mail a copy of your response to "asi@enginia.com".

Thank you.

Ali Asi
asi@enginia.com

Ali Asi

Re: Edit box with units

Haakon S.4-Jun-02 8:46

Re: Resource ID's at runtime

4-Jun-02 8:46

I am using a system doing exactly what you are asking for.

1. First, you establish a vector of UINT's where the user enters all preferences. For example, length is put in m_UnitVector[2].

2. Secondly, you establish the options in a pairs of const char* and conversion factors:

const char* CUnit::m_Length[]={" [m]"," [ft]"," [mm]"," [in]",NULL};
const float CUnit::m_fLength[]={1.0F,3.280839F,1000.0F,39.37008F};

Here, length is stored in meters as the base unit.

3. In your edit box showing the unit you enter m_unit.m_Length[m_UnitVector[2]], in the box showing the number you show m_fMyLength*m_unit.m_fLength[m_UnitVector[2]]. Of course, when you go the other way with UpdateData(TRUE), you divide instead of multiply.

Hope you can make use of this.

Regards, Haakon S.

Resource ID's at runtime

Aaron Schaefer4-Jun-02 5:39

Aaron Schaefer

4-Jun-02 5:39

Hi All,

I've got a CFormView derived class, where I am creating controls at runtime and placing them on the form. This seems to work OK, but I am wondering how to get some resource ID's to use with theswe controls at runtime. SHould I just reserve a bunch of them, or is there a way to get them dynamically?

Thanks,

Aaron

Joaquín M López Muñoz4-Jun-02 6:23

Joaquín M López Muñoz

4-Jun-02 6:23

If you won't use these IDs later, then you can assign 0xFFFF to all the dynamically created extra controls (I've done it in the past and it worsks.)

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo

Re: Resource ID's at runtime

Aaron Schaefer4-Jun-02 6:22

Aaron Schaefer

4-Jun-02 6:22

Well, the problem is that I have an existing control that the label control is associated with. I create these two controls, a sort of super duper edit control, and its buddy, a static label, dynamically. The edit derived control has a method, something like SetBuddy(int nResourceID) that takes a resource ID to the associated label. For my own use, I have been just saving the window handles to talk to the controls, but the edit control needs a resource. I had been just setting them to 0, without any trouble.

stepping over api calls causes exceptions

moredip4-Jun-02 5:40

4-Jun-02 5:40

Ok, I posted something about this yesterday, and here is some more info:

The basic problem is that whenever I try to step over an API call (InitDialog(), CoCreateInstance(), etc) I get the same exception being raised:

0XC0000005: Access Violation

This only happens when I'm stepping through code. The exception always seems to be raised at the same assembly instruction:

mov eax,fs:[00000018]

I guess this is something to do with the debugger not coping with external function calls, but I can't figure out what is going on other than that.

If anyone needs more information I'd love to provide it, just ask Smile | :)

I hope someone knows what's going on here...

TIA,

Pete

dazinith4-Jun-02 5:47

dazinith

4-Jun-02 5:47

Is this stepping over any call such as this, or is this a specific class's InitDialog() and CreateInstance() calls?

-dz

moredip4-Jun-02 6:00

4-Jun-02 6:00

Seems to be any call like this, not restricted to specific classes, or specific API calls.

dazinith4-Jun-02 6:07

dazinith

4-Jun-02 6:07

ok.. does it compile and run fine, and only crash when you are debuging?

could you give the top level code where you are actually overriding OnInitDialog and what line it is crashing.. because going that deep into the assembler means nothing to me Smile | :)

p.s. if it compiles and runs fine and is just messed up when you are debugging then im clueless Smile | :)

-dz

moredip4-Jun-02 6:22

4-Jun-02 6:22

Yeah, it compiles and runs great normally, it just falls over when I try debugging.

It's not specifically overriding functions that causes problems, it's just calling them.

the assembly means nothing to me either, but I thought it might be a good clue for someone Smile | :)

Rama Krishna Vavilala4-Jun-02 6:25

Rama Krishna Vavilala

4-Jun-02 6:25

moredip wrote:
the assembly means nothing to me either, but I thought it might be a good clue for someone

What is the line above the line. fs:[0000018] is the thread environment bock. Puzzling that it crashes there.

Rage4-Jun-02 6:47

Rage

4-Jun-02 6:47

Are you using .dll ? Are you sure these are compatible with debug mode ? When you say it compiles and runs, is it in Debug or Release ?

~RaGE();

moredip4-Jun-02 7:13

4-Jun-02 7:13

I'm using "MFC as static library". I think they're the standard debug libs, cos they worked fine until about a day ago Frown | :(

- and no, I can't think of anything I changed.

It compiles and runs in Debug mode.

moredip4-Jun-02 7:17

4-Jun-02 7:17

here's the function that fails:

BOOL DProjectLoader::OnInitDialog() 
{
	CDialog::OnInitDialog(); //dies here
...
...

here's the call stack:

KERNEL32! 77e83a14()
CThreadSlotData::GetThreadValue(int 1) line 259 + 12 bytes
CThreadLocalObject::GetData(CNoTrackObject * (void)* 0x00564410 CThreadLocal<_AFX_THREAD_STATE>::CreateObject(void)) line 400 + 17 bytes
CThreadLocal<_AFX_THREAD_STATE>::GetData() line 173 + 13 bytes
CThreadLocal<_AFX_THREAD_STATE>::operator _AFX_THREAD_STATE *() line 183 + 15 bytes
AfxGetModuleState() line 235 + 10 bytes
AfxGetResourceHandle() line 22 + 11 bytes
CWnd::ExecuteDlgInit(const char * 0x000000bd) line 3248 + 5 bytes
CDialog::OnInitDialog() line 670 + 15 bytes
DProjectLoader::OnInitDialog() line 71

here's the assembly:

...
...
...
77E839EC   pop         eax
77E839ED   ret
77E839EE   or          eax,0FFFFFFFFh
77E839F1   ret
77E839F2   mov         eax,[7FFE0018]
77E839F7   mov         edx,dword ptr ds:[7FFE0014h]
77E839FD   cmp         eax,dword ptr ds:[7FFE001Ch]
77E83A03   jne         77E839F2
77E83A05   mov         ecx,dword ptr [esp+4]
77E83A09   mov         dword ptr [ecx],edx
77E83A0B   mov         dword ptr [ecx+4],eax
77E83A0E   ret         4
77E83A11   push        ebp
77E83A12   mov         ebp,esp
77E83A14   mov  <----  eax,fs:[00000018]  //!!FAILS HERE!!
77E83A1A   mov         ecx,dword ptr [ebp+8]
77E83A1D   cmp         ecx,40h
77E83A20   jae         77EB86EB
77E83A26   and         dword ptr [eax+34h],0
77E83A2A   mov         eax,dword ptr [eax+ecx*4+0E10h]
77E83A31   pop         ebp
77E83A32   ret         4
77E83A35   push        ebp
...
...
...