alloca() portability

Sean Fagan seanf at sco.COM
Fri Nov 16 20:29:31 AEST 1990


In article <PAULB.90Nov12131357 at hcx2.ssd.csd.harris.com> paulb at ssd.csd.harris.com (Paul Beusterien) writes:
>There can be major time and space gains by using alloca instead of malloc
>and free.  It is obviously faster to adjust a stack pointer than to search
>an available list and free it back up.  

``Stack pointer''?  What is a ``stack pointer''?

On some of my favorite machines, there is no concept of something called a
``stack.''  (Well, actually, the Cyber has a "stack," but its "stack" is
actually a 10-word instruction queue.)

I just tried a small program, and using alloca() caused a coredump.  You
know, I think you're right:  that saved me *so* much time, space, and
effort!  I'm *so* glad I used it!  (Note for the curious:  if trying to
generate code that will break, it is ofttimes helpful to know the compiler
somewhat intimately 8-).)

Lessee... we've had Chris and Doug denounce alloca(), but I haven't seen
anything from Henry (yet?  I suspect he would also denounce it).  Dennis?

-- 
-----------------+
Sean Eric Fagan  | "*Never* knock on Death's door:  ring the bell and 
seanf at sco.COM    |   run away!  Death hates that!"
uunet!sco!seanf  |     -- Dr. Mike Stratford (Matt Frewer, "Doctor, Doctor")
(408) 458-1422   | Any opinions expressed are my own, not my employers'.



More information about the Comp.lang.c mailing list