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It is better to catch exceptions by reference rather then by value as is in your sample code. i.e.
try
{
..
}
catch(const CException1 & Error)
{
...
}
First it's more efficient as no copying occurs. More importantly it avoids slicing and thus allows you to make a catch class with virtual functions. This is one way to avoid catching so many different exceptions types: instead you catch a base class with virtual functions by reference and make use of polymorphism.
Steve
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Stephen Hewitt wrote: It is better to catch exceptions by reference rather then by value as is in your sample code
VisualCalc actually catches its exceptions by reference. the OP typed it wrong.
Stephen Hewitt wrote: it [...] allows you to make a catch class with virtual functions
exactly what it does...
Stephen Hewitt wrote: This is one way to avoid catching so many different exceptions types
it is also. actually, VisualCalc Parser provides a base class for all its exception classes, but i still catch each exception category one by one to provide a visual feedback to the calculator user... like this, he finally know if he did a syntax, mathematic of whatever kind of error in his expression...
TOXCCT >>> GEII power
[VisualCalc 3.0 updated ][Flags Beginner's Guide new! ]
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hi denny,
why didn't you ask this at the bottom of the VisualCalc[^] article ? i would have asked immediately...
for your question, note that i don't catch the exceptions like you do (by copy : catch(CException1 pError)) but by reference (catch(CException1& pError)) which is trully different for the memory management.
about the many catch blocs, there's no problem with that. you can have as many catch as you like without altering the performances...
you can however reduce the number of catches (design matter) as i provide a base class for all the Parser exceptions (CVCAlcParserException class), but by doing this, you wouldn't be able to tell the user if he gets a syntax, a mathematic, or whatever kind of error...
that's all i think.
if you have any other questions, don't hesitate to ask on the article's message board 
TOXCCT >>> GEII power
[VisualCalc 3.0 updated ][Flags Beginner's Guide new! ]
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hi all 
I saw this code :
inline int foo (char* pBuffer, const char* formatString) throw() {
assert (pBuffer);
assert (formatString);
return "something";
}
If i use this code and in Release build and pass pBuffer, whose value will be NULL, than I get a bug yes ? these asserts are useful only in debug mode, not ?
Is not it better to above this function like this :
inline int foo (char* buffer, const char* formatString) {
if(NULL == buffer)
throw someException();
if(NULL == formatString);
throw someOtherException();
return "something";
}
In this case if we catch the thrown exception than, we are secure in both Release ana Debug builds, not ?
so why use asserts and not throws?
thank you
-- modified at 4:01 Monday 29th May, 2006
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Programming errors are not exceptions. You can't remove bugs until and unless you fix them.
Once you have found and fixed all of the bugs,the assert macros are no longer necessary and you should turn them off by defining the NDEBUG macro.
Assertions show that you are still testing and debugging your code.
An exception is an unpredictable but expected event which cannot be prevented and must be handled.
Exceptions should be handled to the extent possible at the point where they are first detected.
Somethings seem HARD to do, until we know how to do them.
_AnShUmAn_
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_AnShUmAn_ wrote: Once you have found and fixed all of the bugs
How can you know that you have eliminated all bugs ?
_AnShUmAn_ wrote: Assertions show that you are still testing and debugging your code
I see asserts in already posted codes...
_AnShUmAn_ wrote: An exception is an unpredictable but expected event
 , why unpredictable.
Can not understang it fully 
anyway thanks for reply
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if the application is performing as per your expectations with no errors or CRASHES you should know that all the bugs are fixed. It's that simple.
So when you are done with this disable all ASSERTS by defining nDEBUG macro.
Exceptions are unpredictable because in some applications if many threads are running simultaneously than there may be a variable that would get modified in the other sections and cause an exception in another block but this is not guaranteed . It depends on the time the system allocates to each thread.
Somethings seem HARD to do, until we know how to do them.
_AnShUmAn_
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asserts are using only for debug pupose.
suppose if ur buffer getting NULL a endless loop or a lengthy looop, u need not to debug the each loops.
if an assertion occrurs then it will show "This expression failed at this line of source code" then u can trace and correct the bug.
never put ur logic inside the assert macro. because it wont work in release build.
in release build VERIFY macro will satisfy u with the same functionality of assert offer.
I think asserts and exception standing at different areas of erro handling.
We are used to compare with strctured error handling and the normal error handling we are used to follow in "C".
it is depends on ur system to select which is suitable. each mechanism has its own advantages and disadvantages.
SaRath
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I've got an app created as an ANSI Build and want to use a few controls such as an Edit control (CEdit) as Unicode, if running on Win2K or later. I don't want to build the app as Unicode at this time, as I want to support W98 and don't want to have to use the MS W98 Unicode Layer.
I've pretty much spent the day Google'ing and reading and it seems doable, but I've yet to find any concrete info on how. One idea is to provide my own implementation of CWnd::CreateEx() that calls CreateWindowExW() if we are running on W2K/XP etc. but I suspect there is more to it than that.
Has anyone done this or have any suggestions? Mucho thanks in advance.
Neville Franks, Author of Surfulater www.surfulater.com "Save what you Surf" and ED for Windows www.getsoft.com
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If the app itself is unicode unaware, then how do you expect a child window of the app to handle unicode? You will have to do a unicode build to make the app work with unicode as far as I know.
Neville Franks wrote: it seems doable
In case if you did it, please post a reply here and I am very much interested to know how it is.
![Rose | [Rose]](https://codeproject.global.ssl.fastly.net/script/Forums/Images/rose.gif)
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I am a begineer in VC++/MFC can I get some good samples or information links to start learning Multithreaded programming.
"No Defeat Is Final Until You Stop Trying"
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Start here[^].
--
Roger
It's supposed to be hard, otherwise anybody could do it!
Regarding CodeProject: "resistance is pointless; you will be assimilated"
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Scorpio wrote: I am a begineer in VC++/MFC can I get some good samples or information links to start learning Multithreaded programming.
What better than these samples...
MTGDI
MTMDI
MTRECALC
MUTEXES Search MSDN with these keywords to get the appropriate samples.
Nibu thomas
A Developer
Programming tips[^] My site[^]
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Nibu thomas wrote: MTGDI
MTMDI
MTRECALC
MUTEXES
IMO, I never liked Threading Sample Provided by MSDN... The article by Mr Joseph, whoes link is mentioned by WhiteSky is one of the best article for learning multithreading programming.
"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow
cheers,
Alok Gupta
VC Forum Q&A :- I/ IV
Support CRY- Child Relief and You
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ThatsAlok wrote: IMO, I never liked Threading Sample Provided by MSDN...
I specially liked the sample MTGDI. These samples are a bit hard to understand but once you get a hang of it you are on a ball. 
Nibu thomas
A Developer
Programming tips[^] My site[^]
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Nibu thomas wrote: Score: 1.8 (2 votes). Rate this message: 1 2 3 4 5 (out of 5)
BTW Who voted you down? let me sort it out
"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow
cheers,
Alok Gupta
VC Forum Q&A :- I/ IV
Support CRY- Child Relief and You
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ThatsAlok wrote: BTW Who voted you down?
Of course someone didn't like the suggestions that were given. I guess that is what voting is all about.
ThatsAlok wrote: let me sort it out
Thanks.
Nibu thomas
A Developer
Programming tips[^] My site[^]
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See Here[^] for threads maybe it is some helpful to you
whitesky
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I have created a splitter window inside another one as follows:
m_wndSplitter2.CreateStatic(&m_wndSplitter,1,2,
m_wndSplitter.IdFromRowCol(0,1));
ceated the two views
Now i have created a third splitter window
m_wndSplitter3.CreateStatic(&m_wndSplitter2,2,1,
m_wndSplitter2.IdFromRowCol(0,1));
m_wndSplitter3.CreateView(0,0,RUNTIMECLASS(CMyView),pContext);
Here i am getting an Exception.
When i debug the program, iam getting the exception at pNode=m_pNodeHead in LIST_P.cpp
Anybody plz solve my problem
Thanks in advance.
-- modified at 3:14 Monday 29th May, 2006
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sruti_p wrote: Here i am getting an Exception.
When i debug the program, iam getting the exception at pNode=m_pNodeHead in LIST_P.cpp
Check the call stack to see which statement of your file caused this error.
Nibu thomas
A Developer
Programming tips[^] My site[^]
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I am not getting any error When i wrote
m_wndSplitter3.CreateStatic(&m_wndSplitter2,2,1,
m_wndSplitter2.IdFromRowCol(0,1));
m_wndSplitter3.CreateView(0,0,RUNTIMECLASS(CMyView),pContext);
in OnCreateClient().
I am getting the exception only when i wrote the above statements in amy own function. I have written
int id=m_wndSplitter2.IdFromRowCol(0,1);
m_wndSplitter2.DeleteView(0,1);
m_wndSplitter3.CreateStatic(&m_wndSplitter2,2,1,id);
m_wndSplitter3.CreateView(0,0,RUNTIMECLASS(CMyView),pContext);
m_wndSplitter3.CreateView(1,0,RUNTIMECLASS(CMyView),pContext);
Can't we create the splitter window in a function other than
OnCreateClient()?
I am getting the exception at
POSITION CPtrList::Find(......)
{
ASSERT_VALID(this);
CNode* pNode=(CNode*)startAfter;
if(pNode==NULL)
{
pNode= m_pNodeHead;====>here i am getting the exception
}
.......
...........
}
This code is present in LIST_P.cpp.
When i debug the program, i am getting the exception at
mov ezx,dword ptr [edx+4]
I don't know why i am getting this exxception.
can anybody tell me why i am getting this exception 
Thanks in advance.
-- modified at 0:36 Tuesday 30th May, 2006
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sruti_p wrote: This code is present in LIST_P.cpp.
I don't know why i am getting this exception.
can anybody tell me why i am getting this exception
I know the exception is in the file LIST_P.cpp. But it could be caused by one or more statements in your file i.e. in the OnCreateClient function. So that's why I told you take a look at the call stack. Try to comment out all statements in the OnCreateClient. Then Uncomment all the others one by one. Trying the find out who is the real culprit.
Nibu thomas
A Developer
Programming tips[^] My site[^]
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I did what u told me to do.But i am not at all getting any exception because of the code in OnCreateClient(). I am getting th eexception only when i wrote the code in my function. I am not able to understand the reason for this. Can i create the splitter window in a function other than OncreateClient()???
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sruti_p wrote: I am getting th eexception only when i wrote the code in my function. I am not able to understand the reason for this. Can i create the splitter window in a function other than OncreateClient()???
AFAIK No! OnCreateClient is the function that is called during the creation of the client area. Hence you must create your splitter there.
Nibu thomas
A Developer
Programming tips[^] My site[^]
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