Re: Adding <alloca.h> ?

[Mouse <mouse%Rodents-Montreal.ORG@localhost>]

> If some software expects an <alloca.h> but the base OS does not
> provide it, then is it more useful to have a devel/alloca package
> which can be buildlinked which would provide it?

I'm not sure whether that can be done even in principle.  I don't
really understand alloca all that well, but my impression is that it
works by fiddling the stack pointer, and, as such, really needs to be a
compiler builtin.  On some architectures, yes, stack and frame pointers
may be separate and the compiler may be nice enough to generate code
that tolerates a routine returning with the stack pointer moved.  But
that does not sound to me like anything to count on.

Could someone check (and, if appropriate, correct) my understanding?

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