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In general the best thing to do with an access violation in some DLL you don't have source code for is to crash. It's amateurish to think that catching it solves any problems. If you think about it, it's self evident:
- Something went wrong.
- The unexpected event happened part way though a sequence of steps that probably should have been atomic.
I'll give some specific examples of the kind of problems that could occur:
- You were adding a node to a double-linked list when the access violation occurred. Now you have a node that is only partially linked in. Instead of crashing at the point of insertion you crash down the track when iterating over the list.
- The access violation happens after a call to
EnterCriticalSection but before the corresponding LeaveCriticalSection. Instead of crashing at the problem location an entirely different thread now locks up.
- The crash was the last of a series of memory accesses of which some of the earlier ones (that didn't cause a crash) corrupted the heap. You'll now crash at some later time when allocating or freeing memory.
You could come up with a million of these examples. In most cases "recovering" from low-level exceptions by catching them turns a bad problem into a worse one. Sometimes crashing is a feature; don't make things worse trying to "fix" things.
You may already know all this (you did mention something about terminating correctly), but I thought it best to point out just in case. There's also the fact that moving the manifestation of a problem (a crash) even slightly from the source of the problem makes it many times harder to fix in future.
Steve
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If you are calling DLL functions, check whether you are passing correct parameters, if any?
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I don't completely agree. While I agree that if there is an access violation in some DLL then program is in unstable state but crashing it (and letting OS tell you that you got a bad application) is bit extreme. I believe that such cases must be detected and a meaningful error must be displayed to user before closing the application. To me such application looks more professional.
-Saurabh
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The user will be more appreciative when the bug is fixed because the crash caused a report to be sent to Windows Error Reporting[^] which was download and analysed by the software publisher.
A software company that develops software but doesn't collect these reports (or use some other 3rd party system of a similar nature) is doing it wrong.
In most cases a custom message will be no more "meaningful" than a crash, but a crash is more constructive (it sends an error report to MS) and the state of the program has not altered by some custom "something ain't working" error dialog (and thus making analysis harder).
Steve
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hi everybody.
now, i wish help for me this matter.
when I update field "Pass" of table USER. if table USER have 10 records, but when update to records 5 ==> error, i need rollback all data when table not update, but if update 10 records success ==> update all.
thanks very much.
nothing
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You posted no code (you even did'n mention the database you are dealing with): how can we help you?
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
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Rollbacks should be supported by the database.
So in C you should start a "transaction" which could get rolled back.
Press F1 for help or google it.
Greetings from Germany
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this matter need application of VC++6.0 support, because SQL Server not support. sql server only support transaction 1 record.
in C# it support this application by Transaction, but in VC++6.0 I don't know. wish your help.
thanks very much
nothing
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aa_zz wrote: because SQL Server not support. sql server only support transaction 1 record.
I bet my 2 cents the above sentence is false.
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
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i agree with you. but if you using plus string, it can update more records, but it will overload string  .
nothing
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aa_zz wrote: but if you using plus string, it can update more records, but it will overload string
I don't get you. 
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
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i think, we can using "registry" to do it, but i don't using it. for examble :http://www.codeproject.com/KB/vista/VistaKTM.aspx
nothing
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consider learning something about databases!!!
i guess that you are guessing. 
if you have any question please pot also some code 
Press F1 for help or google it.
Greetings from Germany
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Hi all,
i m working on sending SMS application by AT Commands,
here Nokia,Sony,LG,Samsung mobile working ok.
now i want to connect blackberry here,but its not able to sebd sms by AT commands in case of blackberry.
please tell me ,
is black berry not supported AT commands for Send SMS.
thanks.
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I think you are asking this at the wrong forum, maybe try the Mobile Development[^] section...
> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> Sometimes you just have to hate coding to do it well. <
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Hi
I am using sdi.(in windows explorer style)
treeview in left view...
formview in right view ...each form appears upon clickin the items in tree.
how to transfer data between forms .....??
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Usually, you shouldn't do something like that (have each form communicating directly to each other). In a SDI application, you have a document, which is used to keep the "data". The views (in your case the treeview and formview) only display the state of the document. Whenever the user changes something on a view, this modifies the data contained in the document which is then informing all the views to refresh themselves.
This way, there's no exchange of data between the different views.
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Hmmm..Can u prvide any tutorials or examples to follow up
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See here.
"One man's wage rise is another man's price increase." - Harold Wilson
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
"Man who follows car will be exhausted." - Confucius
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Hi
i am declaring a global variables in SDI Appplicatin..
How to use this globl variables in other formviews??
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If I understand you correctly, first declare your variable in a file such as 'Globals.h' and add that file to the project.
int g_MyVariable = 0;
Then declare it with the keyword 'extern' before it in a file called for example 'Externs.h'.
extern int g_MyVariable;
Then include that file in any cpp files that need toa access the gloabl variable.
#include "Externs.h"
Be carefull about using globals though, only use them where absolutely essential, otherwise stick to local variables - they are much easier to manage.
Ali
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Hi
My Doubt is how to call this glboal variables in other forms...
Well i declared like this
1. Declare "static CString g_m" in APP.h
2.Declare CString CISApp::g_m = NULL in App.cpp
3.Use CISApp::g_m where ever you want to use
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in that case you have to declare static CString g_m in the class !!!
Press F1 for help or google it.
Greetings from Germany
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