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From: ano@blake.acs.washington.edu (John Michael Ano)
Newsgroups: comp.windows.ms
Subject: Memory Management & Data Structures
Keywords: linked lists, moveable data segments
Message-ID: <3033@blake.acs.washington.edu>
Date: 31 Jul 89 17:26:35 GMT
Reply-To: ano@blake.acs.washington.edu (John Michael Ano)
Distribution: comp.windows.ms
Organization: University of Washington, Dept. Psychology, Seattle
Lines: 21

What is the best way to generate and maintain a linked list or B-tree in
memory using Windows' memory management scheme?  I'm working with relatively
small structures (elements < 50) and they have a fairly long life-span.   
So I'm torn between allocating space in either the global or local data
segment.  For now I've decided that the structures are small enough to
sit in the local DS, and now I'm wondering what the best way to allocate
memory is.  Is it wiser to allocate one big block and do lots of pointer
arithmetic to maintain the list, or should I allocate one small block for
each element and use the handles generated by LocalAlloc() to get pointers
(with LocalLock()) to adjacent nodes?  The drawback with the second method
is that I have to lock and unlock each node to traverse the list.  It seems
awkward, but Petzold mentions that the GlobalLock and GlobalUnlock functions
are fairly fast, and I assume the same applies to the local versions even
though he says nothing about them. 
The allocated blocks are all allocated as LM_MOVEABLE so that Windows can move
the blocks when memory gets scarce.  How have other people dealt with data
structure management under Windows?

John Ano
Dept. Psychology
UW