RE: stack overflow bug in ofstream::operator<<

[Igor Pechtchanski <pechtcha at cs dot nyu dot edu>]

On Tue, 28 Jun 2005, Dave Korn wrote:

> ----Original Message----
> >From: Igor Pechtchanski
> >Sent: 28 June 2005 19:10
>
>   Ok, I'm following you up to this point ...
>
> >  Checking the stack size every time will introduce equal
> > overhead on both paths,
>
>   ... but now you've lost me.  How does checking the stack space make the
> alloca path take as long as the malloc path?

That's "equal overhead *on top* of the alloca/malloc costs".

> > but I'm not sure we can do better (besides, the overhead should be
> > pretty small -- a memory read followed by a pointer comparison).
>
>   Umm, this is all completely lost in the noise next to the difference in
> execution times between malloc and alloca isn't it?

It is for malloc.  Alloca is cheap enough that this may be noticeable.
	Igor
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