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Hi !
In our team, we used to develop COM/DCOM components for our applications. That made it easy to work in separate entities and not having to merge code.
But now, we have to develop a crossplatform application, which means COM/DCOM is not a usable solution.
I heared a little about CORBA, but I'm wondering if anyone of you already used it, or if I should use something different. And what about the price for a commercial application ? Is CORBA free ?
Thank you for your help !
Jerome
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COM is actually available on a number of UNIXes, and there's been an on going .NET type compiler for Linux/BSD.
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CORBA is simply a spec. What costs are the various implementation of the CORBA spec, typically referred to as a CORBA ORB (Object Request Broker). There are a number of good impls out there that are free. The two that come to mind are :
Mico[^]
TAO[^]
Both are written in C++ and supposed to be quite good, and both are cross platform.
CORBA is supposed to be a bit complex to get working/using, though if you have a lot of COM experience, I doubt it's much worse of a learning curve.
You might consider using Mozilla's XPCOM[^] which is nearly identical to how MS's COM works AFAIK. It support C++ as well and also runs cross platform.
Cheers
¡El diablo está en mis pantalones! ¡Mire, mire!
Real Mentats use only 100% pure, unfooled around with Sapho Juice(tm)!
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Dear MFC Gurus,
I have been struggling with a simple MFC demo. The project is basically for a tree view control, there are two views, the left view and the right view. The left view is derived from CTreeView and the right one from CEditView,the two views are separated by a Splitter window.
The project is designed to work as follows
On the left hand side are numbers (1,2,3,4...10)
When I click on 1,2,3.. (which is the parent), the children(1.1,1.2,1.3....1.9) are supposed to appear on the right side (The Edit View Window).
I found a similar example on this site but did'nt quite understand the programming logic behind it!
Could any body kindly make this project up for me, I am in the learning stages and would appreciate such valuable contributions..
hoping for the best
rahul
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The best way to learn is to try to do it yourself and ask specific questions along the way. Don't ask for people to do your work(homework?) for you. Use some initiative. You will go a long way if you problem solve tasks like this yourself. I'm not trying to be mean, just giving advice.
Best of luck!
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hi Tim,
Alright, here is the specific question, so far I have managed to have the tree view control and it does display the parent and children on clicking, with the static splitter window I see the same view on both sides, however this is not what I need! I need the children to be displayed on the right side.(CEditView)
I have an idea of mouse event functions such as OnSelChange that handles Tree View control notifications and takes care, but am not able to implement it.
For your information, I have created a class called Numbers that has an Index (Parent) and a CStringArray (Call it Child)that would hold the children.
All these objects referred as Numbers are stored in a CArray called Number_Array.The Numbers_Array and the Child are being populated in the OnInitialUpdate function of the CTreeView class.
I have been trying my best to get this through, I am also of the opinion that self help is the best way to learn, but at this point I feel completely lost and hence the question!
It would be great if you could reply
thanks
rahul
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Hello Rahul,
It appears you already have the CSplitterWnd member variable added to your SDI frame or MDI child frame(not sure which you're using). To add the edit view you need to override the OnCreateClient() function of the frame window containing the CSplitterWnd member variable .
Example:
BOOL CSplitFrame::OnCreateClient(LPCREATESTRUCT lpcs, CCreateContext* pContext)
{
CRect rect;
CSize size;
GetClientRect( &rect );
size = rect.Size();
size.cx /= 2;
if (!m_wndSplitter.CreateStatic(this, 1, 2))
{
return FALSE;
}
if (!m_wndSplitter.CreateView(0, 0, RUNTIME_CLASS(CYourTreeView), size, pContext)
{
TRACE("Failed to create tree view.");
return FALSE;
}
if (!m_wndSplitter.CreateView(0, 1, RUNTIME_CLASS(CYourEditView), size, pContext)
{
TRACE("Failed to create edit view.");
return FALSE;
}
return TRUE;
}
If you are using the standard doc-view architecture, there is a CDocument derive class that is shared by the two views. When you click on an item in your tree view, you can update a variable in the document which contains the number that was selected. After that document varialbe has been updated, you can UpdateAllViews and have the OnUpdate function of the CEditView display the data stored in the document. Remember, the purpose of the document object is to store the data the views need to display that data.
Happy programming!
Tim
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hi Tim,
Thanks for the snippet, I am doing as you have suggested,I have created the function
OnSelChange(NMHDR *pNMHDR,LRESULT *pResult)
{
NM_TREEVIEW *pNMTREEVIEW = (NM_TREEVIEW*) pNMHDR;
CTreeCtrl &tree = GetTreeCtrl(); // Get the Tree Control reference
HTREEITEM hItem = tree.GetSelectedItem();// Get the currently selected item
*temp = tree.GetItemData(hItem); // Get the item value in this case 1,2,3.. I suppose
CString item_data = temp;
CTree1_ExampleDoc * pDoc = GetDocument(); // Get hold of the document
// Get the children of the selected item and update the document object!
for(int i=0;i<num_array.getsize();++i)
{
="" numbers="" num;="" refer="" below="" for="" the="" number="" defn.
="" cstring="" sfulllist;
="" num="Num_array.GetAt(i);
" if(item_data="Num.index)
" pdoc-="">Doc_Number.index= item_data;
for(int k=0;k<num.child.getsize();++k)
{
="" pdoc-="">Doc_Number.Child.Add(Num.Child.GetAt(k));
sFullList =sFullList+Num.Child.GetAt(k)+"\r\n";
}
break;
}
}
GetDocument()->SetModifiedFlag();
GetDocument()->UpdateAllViews(this,1L,(CObject*) &sFullList);
}
In the EditView Class there is a function OnUpdate listed below,for which I am retrieving the updated document object.
void CTree1_ExampleView::OnUpdate(CView* pSender, LPARAM lHint, CObject* pHint)
{
// TODO: Add your specialized code here and/or call the base class
if(lHint==1L)
{
CEdit & theEdit = GetEditCtrl();
// sFullList = ((CString*)pHint)->GetBuffer(0);
CTree1_ExampleDoc *pDoc = GetDocument();
Numbers View_Number;
View_Number.index = pDoc->Doc_Number.index;
CString sFullList;
for(int i=0;i<pdoc->Doc_Number.Child.GetSize();++i)
{
View_Number.Child.Add(pDoc->Doc_Number.Child.GetAt(i));
sFullList = sFullList+pDoc->Doc_Number.Child.GetAt(i)+ "\r\n";
}
// AfxMessageBox(sFullList);
theEdit.SetWindowText(sFullList);
this->Invalidate();
}
}
This however is not displaying the text in the edit window.
// Definition for Numbers
class Numbers
{
public:
CString index;
CString sub_index;
CStringArray Child;
Numbers& operator=(Numbers &num)
{
index = num.index;
sub_index = num.sub_index;
Child.Copy(num.Child);
return *this;
}
};
class Numbers_Array:public CArray<numbers,numbers&>,Numbers
{
};
Last question, How do I get the item currently selected by the mouse, Will I have to write a message handler such as OnMouseClick(); ???
Please suggest.
thanks
rahul
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I'll answer the easy question first.
Question:
rahulmsaxena wrote:
How do I get the item currently selected by the mouse
Answer:
// find the currently selected item
HTREEITEM hCurSel = pCtrl->GetNextItem(TVI_ROOT, TVGN_CARET);
Now for the rest of the project. First of all, I would say you use of the Numbers_Array and CStringArray is overkill for what I understand the project requirements are. Lets simplify quite a bit. Just use one CString variable in your document to store the generated text.
Have your edit control display the text in the CString when OnUpdate occurs. For testing purposes, set the CString to the ASCII equivalent of the value stored in the Tree Controls ItemData that you are using currently. The CEditView should now be displaying the text of the data in the tree item you have slelected with a mouse click.
To get the whole tree heirarchy(1.1.3 for example), write a quick loop that will recursively traverse up the tree control by getting the data of the item's parent until the root of the tree has been reached. Build your string as you go up the tree. Now you won't need any arrays and the code should be able to handle multiple levels of items and their children in the tree.
Trees like this should be easy:
1
2.1
2.2
2.3.1
3.1
3.1.1.1
... and so on.
Tim
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I have a serial device that has a checksum in the communication data packet.
The only description the documentation has is "2's complement of the sum of
all bytes from byte1 to byte n-4". This sound as though I should add all bytes
in the structure from the first byte to the byte before the checksum byte and place the
twos complement of this value into the checksum byte.
When I create a packet and add the bytes together then I get a value that is larger
than a 8 bit value. I have asked the found from asking in other forums and scanning
the internet that a 2's complement is taking a number and inverting all bits and then
adding 1 to it. my problem is that the size of the value should be 8 bits and when I
add them up I get 16 and some times 32 bit values.
I am trying to communicate with this device using VB.Net, I ask this question in the VB.Net
forum but no one has answered. So I thought I would ask here and try to port any answers to
VB. Now that I think I have explained everything my question is:
how do I do a 2's complement of the sum of all bytes in an array and put that value into a single 8 bit byte?
Thank you for any help you can offer.
=================================
When I was in school, all I wanted was to get out into the real world.
Now that I'm in the real world, all I want is to go back to school.
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The checksum is generally the twos-complement of the low byte of the sum, so I would code it like this:
BYTE CalculateChecksum(BYTE *pData, UINT dataSize)
{
UINT sum = 0;
for(int i=0; i<dataSize; i++)
sum += pData[i];
sum = -sum;
return (BYTE)(sum & 0xff);
}Where pData is a pointer to you data buffer, and dataSize is the length of the data. I'll leave it to you to translate this to VB 
Hope this helps,
Ryan "Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late" John Nichol "Point Of Impact"
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Hello Dudley,
It is perfectly acceptable to have the sum of all the bytes "roll over" beyoung the maximum value of the data type you are using, 8 bit or byte. If your running checksum is a byte something like the following will probably happen:
Lets say you want to add the following three bytes 127, 63, and 98. The running 8 bit checksum and 16 bit check sum would be the following.
Checksum Total
Byte (8 bit) (16 bit)
127(0x7F) 127(0x7F) 127(0x7F)
63(0x3F) 190(0xBE) 190(0xBE)
98(0x62) 32(0x20) 288(0x0120)
The 8 bit check sum is just the 8 LSB or the 16 bit checksum.
In your implementation, you can just use a BYTE for your checksum and add all the data bytes, or you can use a larger data type like an int for your checksum and your 8 bit checksum would be the 8 Least Significant Bits.
Don't forget that after you have added all the bytes you need to do the 2's complement.
Invert all the bits and add one.
(C language)
checksum = ~checksum + 1;
The final checksum for the above example would be:
224(0xE0)
When you add the sum of all the bytes and the final checksum together, you should get zero.
32(0x20) + 224(0xE0) = 256(0x100);
But 256 is really 0 for a 8 bit data type (0x00);
Hope this helps.
Tim
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Thanks Guys I think I understand alot better now.
I will reply here when I get this working.
=================================
When I was in school, all I wanted was to get out into the real world.
Now that I'm in the real world, all I want is to go back to school.
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Please help.How to extract audio from AVI fimes using VC++ and DirectX?
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Use DirectShow - it comes with Direct X - try reading the docs
¡El diablo está en mis pantalones! ¡Mire, mire!
Real Mentats use only 100% pure, unfooled around with Sapho Juice(tm)!
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i'm supposed to write an application that detects the laser pointer on the image captured from a webcam(which has an infra-red camera in front of it). so first i'm grabbing a frame(as a bitmap file). next i should process this file(check its pixels one by one) but i don't know how to do that part. is there anyone to help me?
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i assume, that there is a red spot where the laser pointer is!
code kinda filter, which creates a second bitmap in memory...
it should scan the original bitmap line by line, and check the pixels for red.
if they are red, they should be white in the second bitmap, if not, then black.
then you check for a small white spot on the second bitmap and you got it!
Don't try it, just do it! 
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Hello ppl, i am trying to learn multi-threaded c++ programming and have tried the MSDN example. It works fine with just a simple main function and a thread function. But when i try to implement it in a win32 application, i get the following error.
error C2664: '_beginthread' : cannot convert parameter 1 from 'void (void *)' to 'void (__cdecl *)(void *)'
I am using VC++ 6 with the 2003 platform sdk installed. My project is generated by the WTL AppWizard provided with WTL 7.0. I have put my thread function as a member function to the main dialog class. I have included process.h in stdafx.h
_beginthread(ThreadFunc, 0, NULL);<br />
...<br />
void CMainDlg::ThreadFunc(void * dummy)<br />
{<br />
...<br />
}
Any help/pointer will be very helpful. Thankx in advance.
-Tareq
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Have you declared the thread function as a static ?
~RaGE();
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In the Thread function You must specify the
Calling convention of the Function
Like
unsigned __stdcall YourThreadFunction(void* pVoid)
{
return something;
}
and try to write the fucntion a a pubic, not a member
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Thankx Rage for the quick reply. I didnt make the function static. That was the problem. Now it works fine but i have another problem. Can i access any objects declared in the mail dlg class? I have an edit box named _edit. if i use _edit.AppendText("blah blah"), it gives me the following error. 
error C2228: left of '.AppendText' must have class/struct/union type
Thankx again for your response.
-Tareq
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You're inside a static function of a class - therefor you can't access member functions. Typically what people do is pass in a application variable to the thread's void* argument. In your case, this would be a pointer to the instance of your Dialog class. then you could refernece it.
However with that solved your next problem will arise in making changes to UI controls from outside the main UI thread of execution. You must be very careful when doing this or risk causing lock, or various other wicked and evil things to happen. To simplify this, you might consider Posting a message back to your dialog class instance and then accessing the control there. This way you ensure that you're back in the context of the main UI thread.
¡El diablo está en mis pantalones! ¡Mire, mire!
Real Mentats use only 100% pure, unfooled around with Sapho Juice(tm)!
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1. modify your ThreadFunc like this:
void ThreadFunc(void * dummy)
2. call _beginthread like this:
_beginthread(ThreadFunc, 0, this);
3. again, modify your ThreadFunc to call a member function of your CMainDlg:
void ThreadFunc(void * dummy)
{
CMainDlg* m_pDlg = (CMainDlg*)dummy;
if(m_pDlg != NULL)
m_pDlg->ThreadFunc(NULL);
}
regards
modified 12-Sep-18 21:01pm.
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Hi,
Your thread ThreadFunc is CMainDlg mamber. To use
CRT _beginthread try to declare it as separate function as:
void ThreadFunc(void * dummy)
{
}
Or try to use AfxBeginThread, or CreateThread
Hope it help.
Vitali
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Thank you all for your replys. Greg S. your solution worked like a charm and its so obvious ... i only forgot to cast it to the editor pointer inside the thread function.  ... again thank you all for your solutions.
-Tareq
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