how are exception expensive?

Are they expensive because of what happens when an exception is thrown or
because of the extra checking involved when you wrap exceptions around code?

re: how are exception expensive?

"Monster" <monster@this.monster@that> wrote in message
news:hpOdnZWg4IsHFw3dRVn-uQ@giganews.com[color=blue]
> Are they expensive because of what happens when an exception is
> thrown or because of the extra checking involved when you wrap
> exceptions around code?[/color]

This is implementation-specific. According to Stroustrup (TC++PL, p. 381),
"In principle, exception handling can be implemented so that there is no
run-time overhead when no exception is thrown." However, it is known, for
example, that VC++ exception handling does have a run-time cost even when no
exception is thrown. This cost is only small so can be ignored for most
purposes.


--
John Carson
1. To reply to email address, remove donald
2. Don't reply to email address (post here instead)

re: how are exception expensive?

"John Carson" <donaldquixote@datafast.net.au> wrote in message
news:40909b58$1@usenet.per.paradox.net.au...[color=blue]
> "Monster" <monster@this.monster@that> wrote in message
> news:hpOdnZWg4IsHFw3dRVn-uQ@giganews.com[color=green]
> > Are they expensive because of what happens when an exception is
> > thrown or because of the extra checking involved when you wrap
> > exceptions around code?[/color]
>
> This is implementation-specific. According to Stroustrup (TC++PL, p. 381),
> "In principle, exception handling can be implemented so that there is no
> run-time overhead when no exception is thrown." However, it is known, for
> example, that VC++ exception handling does have a run-time cost even when[/color]
no[color=blue]
> exception is thrown. This cost is only small so can be ignored for most
> purposes.
>[/color]

Any cost may also be less than the traditional alternative of checking the
return value of every function call. That obviously has a run time cost, but
even more importantly leads to great difficulties in code maintenance. I've
seen many, many examples of code which is trying to catch rarely occurring
errors in a deeply nested series of function calls, but where the code
doesn't work correctly in the face of errors, inevitably because some return
values aren't checked.

john

re: how are exception expensive?

"John Harrison" <john_andronicus@hotmail.com> wrote in message
news:c6q6i4$f1fjb$1@ID-196037.news.uni-berlin.de...[color=blue]
>
> Any cost may also be less than the traditional alternative of checking the
> return value of every function call.[/color]

Yeah, that's a good point.
[color=blue]
> That obviously has a run time cost, but
> even more importantly leads to great difficulties in code maintenance.[/color]

Well now you're changing the subject :-)