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From: cb@sequoia.UUCP (Christopher D. Brown)
Newsgroups: comp.sys.ibm.pc,comp.lang.c
Subject: Re: Microsoft C - Heap space question
Keywords: heap microsoft-c
Message-ID: <804@sequoia.UUCP>
Date: 7 Sep 89 12:53:17 GMT
References: <3631@cbnewsh.ATT.COM>
Reply-To: execu!cb@cs.texas.edu
Distribution: usa
Organization: Execucom Systems Corp., Austin, Texas
Lines: 23

In article <3631@cbnewsh.ATT.COM> jmn@cbnewsh.ATT.COM (john.b.medamana) writes:
>Is it possible to get a separate physical segment (Group?) 
>for heap?   I am using the Microsoft C large memory model.
>The default allocation combines stack and heap into a 
>single 64K segment (DGROUP).  Is there a way to get a
>separate segment for heap?
>
>I'm using Microsoft C 5.1 and Microsoft LINK.

MSC 5.1 _fmalloc, which is the large model malloc, allocates new, far
memory until all (MS-DOS) available memory has been allocated;  At this
point _fmalloc calls _nmalloc as a last resort.  Thus, ordinarily,
allocation is not from DGROUP.  Note that DGROUP is at the end of
the load and can be extended by _nmalloc ONLY if the memory above
it has not been allocated via _fmalloc, halloc, or direct calls to
the MS-DOS memory allocation primatives.

The library routines halloc and hfree may be of interest.  They map
directly to the MSDOS memory allocation primatives.

Chris Brown
Net: execu!cb@cs.texas.edu
Voice: (512) 346-4980