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I have about 40 controls on a dialog that use OnCtlColor to paint themselves the same background color as the bitmapped background they sit on top of. You can page through multiple pages of data very fast, and the program kept crashing. I noticed while watching task manager, that it was eating incredible amounts of memory on paging, and removed the OnCtlColor stuff, and it stopped eating memory and crashing. Here's what the code looks like:
<br />
HBRUSH CMyDlg::OnCtlColor(CDC* pDC, CWnd* pWnd, UINT nCtlColor) <br />
{<br />
HBRUSH hbr = CDialog::OnCtlColor(pDC, pWnd, nCtlColor);<br />
<br />
switch (pWnd->GetDlgCtrlID()) <br />
{<br />
case IDC_FIELD01:<br />
pDC->SetBkColor(RED);<br />
pDC->SetTextColor(WHITE);<br />
hbr = CreateSolidBrush(RED);<br />
break;<br />
...etc...<br />
return hbr;<br />
}<br />
<br />
What is the best way to handle that problem, and anybody know why it would eat so much memory?
Thanx,
Rick
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Do the CreateSolidBrush() once, perhaps in the constructor. Then just set hbr to that brush handle. In the destructor, be sure to delete that brush handle.
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As prcarp syas, you rcurrently creating a new brush everytime the function is called. Where is this GDI resource being returned to windows? Its up to you to clean it up.
As you dont actually use it yourself, you should make hbr a class member. Call CreateSolidBrush() in your calss constructor and DeleteObject() on it in the destructor.
This should stop you leaking GDI resources.
If you vote me down, my score will only get lower
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Thanx folks - My Bad 
I was under the assumption that Win would clean that up itself, there I go assuming before thinking again...
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Advanced thanks for the suggestion that you are going to give me 
I am running a service that has the functionality of tracking the user log-off. Currently in the service i have a window that captures the WM_ENDSESSION message from windows O/S and i am logging it as a user "log-off event" ,this works fine as long as no activity is done to stop the logoff .In the case when logoff proceeds and an open document is prompted to be saved and the user cancels it, the logoff is also cancelled. In such a situation, according to my current logic, the "Log-off" event is logged which is improper.
Can you please help me with a suggestion for capturing the user log-off event only when the user actually logs off.
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Windows first sends the WM_QUERYENDSESSION message to all applications. If all of the applications respond with a non-zero value, Windows will then send the WM_ENDSESSION message. If any application responds with a 0 to the WM_QUERYENDSESSION message (e.g., document not saved), Windows does not end.
You might also look at the ISensLogon interface.
"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow
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Since some days the debug build of my application crashes when calling the close() and requery()
members of CDaoRecordset and when deleting all recorsets of a table in a loop, the call of delete for the last recordset crashes. Stepping into the MFC code shows that it always occurs at the same place in some code for the DFX mechanism. Since it's the same problem on all my three machines and it appeared "over night", I don't think that it is a bug in MFC. The only changes on all three machines are several service packs/security patches applied from our pc-support guys, so I think the problem is within the MS JetEngine which perhaps was affected by applied patches.
So what would you do now ???
MS
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Manfred Staiger wrote:
Since some days the debug build of my application crashes when calling the close() and requery()
members of CDaoRecordset and when deleting all recorsets of a table in a loop, the call of delete for the last recordset crashes. Stepping into the MFC code shows that it always occurs at the same place in some code for the DFX mechanism. Since it's the same problem on all my three machines and it appeared "over night", I don't think that it is a bug in MFC. The only changes on all three machines are several service packs/security patches applied from our pc-support guys, so I think the problem is within the MS JetEngine which perhaps was affected by applied patches.
So what would you do now ???
1: All Database operations should be enclosed in try catch statements. There are a number of reasons why a data connection could fail and cause your app to crash. For starters make sure its still open before attempting to close it.
2: Why loop through an entire table to delete all of the records? A Delete query is much faster.
3: What versions of jet where you using? What versions are you using now?
Social Engineering Specialist.
Because there is no patch for human stupidity.
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sfdougl wrote:
1: All Database operations should be enclosed in try catch statements. There are a number of reasons why a data connection could fail and cause your app to crash. For starters make sure its still open before attempting to close it.
That's right, but doesn't solve my problem.
sfdougl wrote:
2: Why loop through an entire table to delete all of the records? A Delete query is much faster.
Of course I don't loop the entire table to delete the recordsets. I only wanted to describe that the Delete() call crashes at the last recordset when you do so.
sfdougl wrote:
3: What versions of jet where you using? What versions are you using now?
Unfortunately I don't remember if it has changed. I'm now looking for a PC with an older jet version as the one I have on my machine.
MS
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1: Okay, so what specific error are you receiving?
2: Are you making sure that you have not gone past EOF? Or attempting to delete a record that does not exist?
Source Code and Errors received would greatly expedite the process.
Social Engineering Specialist.
Because there is no patch for human stupidity.
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sfdougl wrote:
1: Okay, so what specific error are you receiving?
There is no exception thrown. A dialog comes up saying "User breakpoint called from code at 0x778813b1". The output window of the editor shows the following messages:
HEAP[TestApp_g.exe]: Heap block at 038C8940 modified at 038C8998 past requested size of 50
sfdougl wrote:
2: Are you making sure that you have not gone past EOF? Or attempting to delete a record that does not exist?
Yes, absolutely. Everything worked fine for more than 2 years and when I make a release build it also works fine.
I made a small example which crashes as described, and works fine as release build.
//CTestClass is derived from CDaoRecordset
//m_nDefaultType member is set to dbOpenDynaset in the constructor
//m_pDatabase member is set to an open database (which contains the table "TestTable")
void CTestClass::DeleteWithLoop()<br />
{<br />
int counter=0;<br />
this->Open(AFX_DAO_USE_DEFAULT_TYPE, "TestTable", 0);<br />
if(!this->IsEOF())<br />
{<br />
while(!this->IsEOF())<br />
{<br />
counter++;<br />
this->Delete();
this->MoveNext();<br />
} <br />
}<br />
this->Close();<br />
}
In the meantime I'm quite shure that it's a bug in the jet engine.
MS
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Sorry it took so long for me to get back to you. I'm on an odd schedule.
1: Good question, I don’t have a clue here.
2: The problem most probably isn't the delete statement but the MoveNext() if you delete the last record and attempted to move to a record that doesn’t exist an error occurs. I have had the same problem. Perhaps, the newer DAO version is stricter about such operations.
When you get a chance can you find out what version of DAO your using? Have any workstations that where not updated?
Social Engineering Specialist.
Because there is no patch for human stupidity.
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Hi all,
I search the size of the childframe border from a mfc view.
I've saved the size and the coordinates to the registry. I use this size to split the view in four equal section.
But doesn't work, because I've not subtract the frame border.
Can anyone tell me the right border sizes from a childframe.
Jens
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Call GetSystemMetrics() (with the appropriate parameter for the border that you are interested in) on the childframe in question.
Ant.
I'm hard, yet soft.
I'm coloured, yet clear.
I'm fruity and sweet.
I'm jelly, what am I? Muse on it further, I shall return! - David Walliams (Little Britain)
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You should be using GetClientRect() to get the area to split your view up into.
If you vote me down, my score will only get lower
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I have two PCs, and I want to setup direct connection via serial port.
I used crossed wire to connect two PCs.
I setup HyperTerminal on two PCs with the same configuation (use COM1 port).
But I cannot send data between the HyperTerminals.
Can any one suggest me ?
Thank you.
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Not really a programming question, however!
Make sure that the cable that you are using is a fully populated NULL modem cable. You ought to be able to communicate given both Hyperterminals are set to the same baud rate etc..
Ant.
I'm hard, yet soft.
I'm coloured, yet clear.
I'm fruity and sweet.
I'm jelly, what am I? Muse on it further, I shall return! - David Walliams (Little Britain)
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Consider several classes like this:
class Class
{
public:
Class& operator&=(const Class& c)
{ return *this; }
};Now consider this template:
template<class A, class B>
A operator&(const A& a, const B& b)
{ return A(a)&=b; }
for any Class-like, now we have & available.
Now, consider a fragment like this
{
....
int i, flag;
....
if(i & flag)
... some action
... other actions
}
Althought not intentional (I didn't wrote that template for that), the compiler use the templetized & operator.
It should not be a problem, but ... for some reasons i becomes NULL because of the templatized operator& execution even if passed as const& (suppose i and flags have no bits in common).
Am I wrong in something or ... it's one of the C7.0 misteries ?
2 bugs found.
> recompile ...
65534 bugs found.
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emilio_grv wrote:
return A(a)&=b;
Did you mean this?
return A(a & b);
You are modifying a by using &=
Ant.
I'm hard, yet soft.
I'm coloured, yet clear.
I'm fruity and sweet.
I'm jelly, what am I? Muse on it further, I shall return! - David Walliams (Little Britain)
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Antony M Kancidrowski wrote:
Did you mean this?
return A(a & b);
No, I meant "create a copy of "a" (through A(a)) and call the &= operator on that copy, that modifies the copy retuning a reference to the copy itself, that is copyed as a return value.
It works perfectly when A is a class having an &= operator defined, but if used with a primitive type, it seems it doesn't generate the copies, modifying the passed "value", even if it is a const&
2 bugs found.
> recompile ...
65534 bugs found.
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emilio_grv wrote:
My bug or C++ bug
Neither: I think it is a compiler optimization/inlining bug.
There is a recurring pattern that is used in most books on the subject and what you are seeing might be why.
I would try the following:
template<class A, class B>
A operator&(const A& a, const B& b)
{ A tmp(a); return( tmp&=b ); }
OR
template<class A, class B>
A operator&(const A& a, const B& b)
{ A tmp(a); tmp&=b; return tmp; }
Hopefully one or both of these will solve the problem, since they provide more than enough information for the compiler to get it right.
INTP
"The more help VB provides VB programmers, the more miserable your life as a C++ programmer becomes."
Andrew W. Troelsen
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I got your point: By splitting the compound instruction you try (and -in fact - it works) to force the compiler to don't optimize.
But I'm still surprised 'bout the following:
- The compilet was told to "disable optimizations", but was still "optimizing"
- the optimization side effects were out of the optimization scope, treating in fact, a constant as a variable.
I didn't test if(2 & flag): whould it turn number 2 into 0 and add 0 to every subsecuent x+2? Terrificant!
2 bugs found.
> recompile ...
65534 bugs found.
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Well the compiler will still do some optimising. The real problem probably lays in how it is inlining the code. I do not have the 7.0 compiler, but it would be interesting to see if it would choke on (2 & flag) with your code. I suspect that it would see that and produce the correct inline code instead of what ever it was producing. The only real way to see what it is doing is to look at the asymbly code, before and after modifying the code.
 No I do not believe it would turn 2 to 0, every place that 2 is in your code is unique to that piece of code, so subsequent statements where 2 is applied is unique. 2 is a true constant where the variable i was a temporay constant with a specific address location.
INTP
"The more help VB provides VB programmers, the more miserable your life as a C++ programmer becomes."
Andrew W. Troelsen
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Hi
I use the CreateEnhMetaFile to create an enhanced metafile. The third parameter is the rectangle which give me the sizeo of the metafile. Is it possible to alter that side after
the creation? This will allow me to scale better my metafile. Ideally I am locking for something like:
CMetaFileDC * pDCMetaFile = .....;
pDCMetaFile->CreateEnhanced(p_dc, filename.data(), &rect, NULL);
rect = new sizes;
pcDCMetaFile->alterSize(rect);
Thanks a lot
Always try to keep things as simple as possible
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Not sure what you're trying to accomplish - you can draw a metafile into any size area you desired. The size passed to CreateEnhanced() is more for future reference than anything else, it isn't enforced.
Shog9
I'm not the Jack of Diamonds... I'm not the six of spades.
I don't know what you thought; I'm not your astronaut...
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