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Hello
dwCopyLen = dwBufSize - dwSkipCount - HVD_HEADER_SIZE;
how can dwCopyLen become 821 when:
dwBufSize = 815
dwSkipCount = 0
#define HVD_HEADER_SIZE 1+2+4+1 //stx+USHORT+DWORD+char
strange huh?
If i split it to three lines:
dwCopyLen = dwBufSize;
dwCopyLen -= HVD_HEADER_SIZE;
dwCopyLen -= dwSkipCount;
I get the correct result.
Why?
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This comes down to the order in which the operands are evaluated. Your first line expands to
815 - 0 - 1 + 2 + 4 + 1
i.e. 814 + 2 + 4 + 1 = 821
Do
#define HVD_HEADER_SIZE (1 + 2 + 4 + 1)
to get the results you are expecting!
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Martyn Pearson wrote:
This comes down to the order in which the operands are evaluated. Your first line expands to
815 - 0 - 1 + 2 + 4 + 1
i.e. 814 + 2 + 4 + 1 = 821
Do
#define HVD_HEADER_SIZE (1 + 2 + 4 + 1)
to get the results you are expecting!
ofcourse 
Why didnt I think of that? 
Many thanks!
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Lesson 1:
Don't use macros unless you can't do without.
const int HVD_HEADER_SIZE = 1 + sizeof(USHORT) + sizeof(DWORD) + sizeof(char);
would have done the job.
Lesson 2:
If you have to embrace macros, embrace them correctly:
braces go 'round the entire expression, and each argument
"Der Geist des Kriegers ist erwacht / Ich hab die Macht" StS
sighist | Agile Programming | doxygen
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Hi, I keep getting an error and I can't work out how to get rid of it
it is Error HC5011: cannot open the file E:\VC98\MFC....\afxhlp.hm
I think this is because I moved my project to a machine with a different path. How can I change the path the compiler uses?
Cheers
Andy
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This is a file referenced in your projects .hpj (help file). Its a text file, so open it up and mod the path to the correct (new) location.
Roger Allen
Sonork 100.10016
Were you different as a kid? Did you ever say "Ooohhh, shiny red" even once? - Paul Watson 11-February-2003
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cheers
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I am using VC6 on a 1.3ghz processor.
My project is fairly large (about 1500 files).
When I double click on a header or file in ClassView it takes up to 20 seconds to actually load it.
Also, during this time, MSDEV is taking >95% of the processor time.
Why?
Can I prevent it?
Neil
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Do you have an excessive amount of breakpints set? (Check (under VC6) with 'Edit/Breakpoints')
Try deleting your *.ncb-file. It gets rebuild on the start of VC++6. That is my standard when soemthing strange happens.
My opinions may have changed, but not the fact that I am right.
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I know others that have mentioned this behavior when opening a project with many files. The VS editor is just not built to handle such a big payload.
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I have a DLL written in VB6(not sure) and need to use it from C++
I created manually .DEF file with names of all DLL functions and generated .LIB
(with LIB /DEF:MyDLL.DEF command)
But C++ adds name decoration if I declare imported function as stdcall,
so there are linker errors
e.g. MyFunc in DLL -> _MyFunc@16 in VC++
How to make it work?
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Wrap the declarations with extern "C"
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no way!
It forces the compiler to generate prolog/epilog code for C calling convention (caller adjusts stack pointer). It corrupts stack in my case becouse calling function uses __stdcall convention (callee adjusts stack before return from function)
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I made an application with MFC, Doc/View architecture and MDI type. Now the users say that it is too hard to understand and they confuse with more documents. Is there a simple way to transform the program in an SDI type ? Or better, is there a way to limit the maximum number of ducuments ? (So I can keep the MDI for expert users).
Thanks.
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You should be able to limit the open/new options by checking how many documents of your doc/view are already open.
In the ON_COMMAND_UI update handler for ID_FILE_NEW and ID_FILE_OPEN you should disable the option if the registered CDocTemplate object for that doc/view type has any open documents:
POSITION pos = pDocTemplate->GetFirstDocPosition();
pCmdUI->Enable(pos == NULL);
Depending on where you disable the commands, you may need to mod how you get the pointer to the CDocTemplate object.
Maybe:
POSITION pos = AfxGetApp()->m_pDocManager->GetFirstDocTemplatePosition();
CDocTemplate *pTemplate = AfxGetApp()->m_pDocManager->GetNextDocTemplate(pos);
Roger Allen
Sonork 100.10016
Were you different as a kid? Did you ever say "Ooohhh, shiny red" even once? - Paul Watson 11-February-2003
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Hi,
I need to write a litle kernel-mode code. I want to see what the following code will do in kernel mode.
<code>
.
.
.
return *((int *) 0);
</code>
Can I write a kernel mode code by using Visual Studio 7. (I do not have DDK)
And please make me some prediction that, what will the above code do in kernel mode.
thanx
karanba
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I don't think this is kernel mode code. This is "I want to crash code"
MOV EBX,0
MOV EAX,[EBX]
RET
So, you're telling the compiler to load what's at address 0 and return it. There's nothing really important there, some compatabilty interrupt table stuff. But you'll just generate an exception, a crash, but nothing important.
To write in kernel mode, consult the DDK.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~<br />
Peter Weyzen<br />
Staff Engineer<br />
Santa Cruz Networks
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I am using a treeview control in an application I am writing and I am trying to come up with an efficient way to store the hierarchial data in it. I considered creating a vector of all the items which included an id of the parent item, but reconstructing the treeview when it is large would be quite inefficient this way. I haven't seen any premade classes to store treeview data, but I was hoping someone could point me to one, or give me some ideas on a good way to store this type of data.
Thanks.
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You could always create a simple hierarchial recursive class to store the data... something like this (not complete):
class TreeNode : public CObject
{
protected:
CString m_cDisplayText;
int m_iIconIndex;
void *m_vpUserData;
CObList m_oChildNodes; // list of TreeNode elements
public:
TreeNode() { m_iIconIndex = 0; m_vpUserData = NULL}
TreeNode(LPCSTR cpDisplayText, int iIconIndex = 0, void *vpUserData = NULL)
{ m_cDisplayText = cpDisplayText;
m_iIconIndex = iIconIndex;
m_vpUserData = vpUserData;
}
~TreeNode()
{ TreeNode *pNode;
POSITION pPos = m_oChildNodes.GetHeadPosition();
while (pPos)
{
pNode = (TreeNode *)m_oChildNodes.GetNext(pPos);
if (pNode)
delete pNode;
}
}
// std accessors....
LPCSTR GetDisplayText()
{ return (LPCSTR)m_cDisplayText; }
void SetDisplayText(LPCSTR cpDisplayText)
{ m_cDisplayText = cpDisplayText; }
void *GetUserDataPtr() { return m_vpUserData; }
void SetUserDataPtr(void *vpUserData)
{ m_vpUserData = vpUserData; }
CObList *GetChildNodes() { return &m_oChildNodes; }
virtual void Serialize(CArchive &ar)
{
if (ar.IsStoring())
{
ar << m_cDisplayText << (DWORD)m_iIconIndex;
}
else
{
ar >> m_cDisplayText >> (DWORD&)m_iIconIndex;
}
m_oChildNodes.Serialize(ar);
}
};
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As I want to display a JPEG file like the one using PictureBox class, is there any class has the same use in Visual C++ ?
thx
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I have seen this before, but I'm using dialog base and as a beginner of VC++, I don't know how to change the idea from DOC base to Dialog base.
pls help
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I'm creating a ocx in VC which is used for a custom protocol. The main handshaking and connecting to remote host etc., will be handled by a VB app.
I only have to read the COM port through my local buffer variable which is set by VB app in OnComm event.
If my input buffer is empty, I need to wait till I get something in my buffer? Can someone pls. help me how I can do that wihtout jamming the application.
Thanks in advance,
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