Re: How and when to use GCPRO?

[Stefan Monnier <monnier@iro.umontreal.ca>]

>>>> Actually, both Fcar and Fcdr can GC (by signalling an error which
>>>> triggers the debugger).
>>> But the debugger will not return.
>> Oh, right,
> Discussions like this worry me. What if the function is later changed to
> call something that can GC? What if it's used in some new context? If
> it's not utterly performance-critical code, isn't it better to be safe
> than sorry and GCPRO anyway? It's not as if it's an expensive operation.
> Premature optimization is the root of all evil, after all.

On most platforms, GCPRO is a no-op, and on those where it's not, it's
never been a major performance issue, AFAIK.  The problem is just that
it makes the code that much more verbose and painful to
write/read/maintain.


        Stefan