Exceptions in destructors
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Will the following code get rid of any exception that might be thrown in a destructor Session::~Session() { try { logDestruction(this); } catch (...) { } } What are the scenarios in which a destructor is likely to riase an exception? I have not seen in any prodution code with a destrcutor having a try/catch clause like above? Comments
I have used similar code in my remote communications classes. My DTOR will close the comm connection, but if the reason the DTOR is being called is because the connection was already broken/disconnected, I needed to ensure that no exception interrupted the normal DTOR chain. It may not be quite what the C++ designers had in mind but it works. At least with MS VC++. Besides, if they didn't want it to work, it woud have explicitly stated so in the ARM.
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Throwing exceptions from constructors or destructors is a bad idea.
"Why don't you tie a kerosene-soaked rag around your ankles so the ants won't climb up and eat your candy ass..." - Dale Earnhardt, 1997
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"...the staggering layers of obscenity in your statement make it a work of art on so many levels." - Jason Jystad, 10/26/2001John Simmons / outlaw programmer wrote:
Throwing exceptions from constructors or destructors is a bad idea.
Huh? :confused:;)
Mark Salsbery Microsoft MVP - Visual C++ "Great job team! Head back to base for debriefing and cocktails."
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John Simmons / outlaw programmer wrote:
Throwing exceptions from constructors or destructors is a bad idea.
Huh? :confused:;)
Mark Salsbery Microsoft MVP - Visual C++ "Great job team! Head back to base for debriefing and cocktails."
It's just something I don't do.
"Why don't you tie a kerosene-soaked rag around your ankles so the ants won't climb up and eat your candy ass..." - Dale Earnhardt, 1997
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"...the staggering layers of obscenity in your statement make it a work of art on so many levels." - Jason Jystad, 10/26/2001 -
John Simmons / outlaw programmer wrote:
Throwing exceptions from constructors or destructors is a bad idea.
Huh? :confused:;)
Mark Salsbery Microsoft MVP - Visual C++ "Great job team! Head back to base for debriefing and cocktails."
I don't know about the ctors but for the dtors, reference Effective C++ Third Edition by Scott Meyers. Specifically, "Item 8: Prevent exceptions from leaving destructors" There seem to be many schools of thought on this type of issue so I'm not claiming this is the gospel truth but it's worth a read.
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I don't know about the ctors but for the dtors, reference Effective C++ Third Edition by Scott Meyers. Specifically, "Item 8: Prevent exceptions from leaving destructors" There seem to be many schools of thought on this type of issue so I'm not claiming this is the gospel truth but it's worth a read.
I wasn't necessarily agreeing or disagreeing with John's comment. I meant more to open up a discussion. As far as destructors goes, I agree. It makes no sense. Destructors aren't called explicitly and when they are called, one would have to have complete knowledge of when. It could be during the unwinding of another exception. It doesn't even make sense for something exceptional to happen during destruction anyway. For constructors, I don't throw exceptions either. Maybe I'm old-school, but I prefer a two-part construction/initialization if error handling is necessary. For constructors I don't agree that one shouldn't throw exceptions. I don't think exceptions should be used for error handling, nor do I think they were meant to be used that way. IMO they were meant for exceptional cirumstances - something that happens out of the programmer and user's control that is unrecoverable. For framework/library development, however, where a programmer may use a class the wrong way, it may be ok. An exception during the design/implementation phase can be useful to me at that stage, maybe providing enough info to show me immediately what I did wrong. Just my rambling 2-cents :) Cheers, Mark
Mark Salsbery Microsoft MVP - Visual C++ "Great job team! Head back to base for debriefing and cocktails."
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Will the following code get rid of any exception that might be thrown in a destructor Session::~Session() { try { logDestruction(this); } catch (...) { } } What are the scenarios in which a destructor is likely to riase an exception? I have not seen in any prodution code with a destrcutor having a try/catch clause like above? Comments
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I wasn't necessarily agreeing or disagreeing with John's comment. I meant more to open up a discussion. As far as destructors goes, I agree. It makes no sense. Destructors aren't called explicitly and when they are called, one would have to have complete knowledge of when. It could be during the unwinding of another exception. It doesn't even make sense for something exceptional to happen during destruction anyway. For constructors, I don't throw exceptions either. Maybe I'm old-school, but I prefer a two-part construction/initialization if error handling is necessary. For constructors I don't agree that one shouldn't throw exceptions. I don't think exceptions should be used for error handling, nor do I think they were meant to be used that way. IMO they were meant for exceptional cirumstances - something that happens out of the programmer and user's control that is unrecoverable. For framework/library development, however, where a programmer may use a class the wrong way, it may be ok. An exception during the design/implementation phase can be useful to me at that stage, maybe providing enough info to show me immediately what I did wrong. Just my rambling 2-cents :) Cheers, Mark
Mark Salsbery Microsoft MVP - Visual C++ "Great job team! Head back to base for debriefing and cocktails."
Mark Salsbery wrote:
Maybe I'm old-school, but I prefer a two-part construction/initialization if error handling is necessary.
I must be old school, too, because that is along the lines of my thinking. I have never put exception handling in the constructors/destructors and I don't plan on doing so. That's my 2 cents :-D
"The clue train passed his station without stopping." - John Simmons / outlaw programmer
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John Simmons / outlaw programmer wrote:
Throwing exceptions from constructors or destructors is a bad idea.
Huh? :confused:;)
Mark Salsbery Microsoft MVP - Visual C++ "Great job team! Head back to base for debriefing and cocktails."
Mark Salsbery wrote:
Mark Salsbery Microsoft MVP - Visual C++
congrats for becoming MVP!
"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
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Mark Salsbery wrote:
Mark Salsbery Microsoft MVP - Visual C++
congrats for becoming MVP!
"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
Thank you Alok! Are you a Visual C++ MVP?? Mark
Mark Salsbery Microsoft MVP - Visual C++ "Great job team! Head back to base for debriefing and cocktails."
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Thank you Alok! Are you a Visual C++ MVP?? Mark
Mark Salsbery Microsoft MVP - Visual C++ "Great job team! Head back to base for debriefing and cocktails."
Mark Salsbery wrote:
Are you a Visual C++ MVP??
yeah i am Visual C++ MVP too! [:)] but it is secret
"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
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Mark Salsbery wrote:
Are you a Visual C++ MVP??
yeah i am Visual C++ MVP too! [:)] but it is secret
"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
ThatsAlok wrote:
but it is secret
Well if I knew about it I'd say Congratulations to you as well! And I'd say I noticed you have been an MVP for a while. But since it's a secret, I know nothing :) Cheers! Mark
Mark Salsbery Microsoft MVP - Visual C++ "Great job team! Head back to base for debriefing and cocktails."
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ThatsAlok wrote:
but it is secret
Well if I knew about it I'd say Congratulations to you as well! And I'd say I noticed you have been an MVP for a while. But since it's a secret, I know nothing :) Cheers! Mark
Mark Salsbery Microsoft MVP - Visual C++ "Great job team! Head back to base for debriefing and cocktails."
Mark Salsbery wrote:
And I'd say I noticed you have been an MVP for a while.
i am mvp for past two year.. but still doing soul searching for same [:)].. he he he it nice to see you here
"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
