help needed about dynamic space allocation

[Matt Landau]

In newsgroup comp.lang.c (article <332 at apple.UUCP>), turk at apple.UUCP 
(Ken "Turk" Turkowski) writes:
>
>There have been numerous responses to get the declarations consistent, so I
>won't belabor them here.
>
>However, I would like to point out the use of a function that can speed up the
>program considerably when you are only allocating temporary variables.  The
>function is alloca(), and allocates memory from the stack, rather than from
>the heap.  The result is that allocation is simpler, and vanishes automatically
>when you exit the routine.

Well, there are going to be a lot of people pointing this out, but I
thought I'd be the first :-)  Alloca is nonstandard, nonportable, and 
doesn't exist on a lot of machines.  In fact, the last time this subject
came up was when a lot of people were having trouble porting Gnu Emacs
bacause it used alloca().  At the time, I think the conclusion was that
there exist machine architectures for which it is practically impossible
to even implement it.

The bottom line: Don't use alloca if you expect your code to port.
-- 
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