🚀 go-pugleaf

In article <4lbd7t$m27@solutions.solon.com>,
John Cochran <jdc@access.digex.net> wrote:
>How about 
>
>4) It exists as a normal function that uses malloc. Every block of memory
>   allocated is placed in a linked list control structure that has a copy
>   of the stack pointer at the time of call.  Whenever alloca is called, it
>   first frees all memory blocks that have a recorded stack pointer
>   (larger or smaller depending on direction of stack growth) than the
>   current stack pointer.  This method doesn't immediately free memory
>   allocated by alloca(), but does keep the number of blocks needing to
>   be released fairly small.  This method is used by the GNU alloca()
>   function supplied with some of the GNU programs.
>

This would break fairly terminally in a program which, say, used
alloca in a single routine which was called repeatedly, each time
allocating a chunk of working memory.  The memory would never get
freed because at each call the stack pointer would be the same
as it was the previous time.

John

-- 
John Winters.  Wallingford, Oxon, England.