🚀 go-pugleaf

Noel S. Gorelick (ngorelic@speclab.cr.usgs.gov.cr.usgs.gov) wrote:
: Bill Whedon (whedon@netcom.com) wrote:
: > Here's the summary I promised.  The answers I got were mixed.  Advice to
: > keep using malloc, advice to use _fmalloc, neither of which solved the
: > original problem (corruption of a linked list).  The most useful was from
: > raymondc@microsoft.com, who sent me a fix for the myfree() routine which
: > stopped my memory leak.  Both routines follow this note.  
: >
: > void *mymalloc(size_t bytes)
: > ...
: >    h = GlobalAlloc(GMEM_FIXED | GMEM_ZEROINIT,(DWORD)bytes);
: > ...
: > 
: > void myfree(void *p)
: > ...
: >       h = (GLOBALHANDLE)SELECTOROF((LPVOID)p);
: > ...
: 
: Question 1)   What is SELECTOROF()?  I am assuming it is the equivalent of
:               GlobalHandle()?
: 
: Question 2)   What do you do about running out of HANDLES?  It has been my
:               expereince, and I have had it confirmed by a few other 
:               programmers, that you only get to allocate about 8000 handles,
: 	      using GlobalAlloc, before you start getting incoherent results...
: 	      Is there any way around this, short of allocating large blocks 
: 	      and doing your own memory management?
: 
: 	      And if there isn't, does someone have a set of routines to do
: 	      this allocation yet?

Yes, there is a limitation on the total number of handles, so you do need to
exercise caution. I also believe that the minimum allocation for GlobalAlloc
is like 4K, so even when allocating something smaller, 4K is reserved. A better
solution is to write a container malloc/free that GlobalAlloc's 4K chunks,
then doles those out, maintaining its own management for the 4K chunks. I
believe that Borland's routines may do some of this type of thing in malloc
and free.

Russ Poffenberger               DOMAIN: poffen@sj.ate.slb.com
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