From: salomon AT uni-wuppertal DOT de (Winfried Salomon)
Newsgroups: comp.os.msdos.djgpp
Subject: malloc() and CWSDPMI 4.0
Date: Wed, 14 Jul 1999 15:34:21 GMT
Organization: University of Wuppertal
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Message-ID: <378bbab9.22414525@news.uni-wuppertal.de>
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To: djgpp AT delorie DOT com
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Reply-To: djgpp AT delorie DOT com

Hello people,

I am a beginner with GNU-compilers and with C and I have a problem
with malloc(), the compiler is GNU C 2.81 under Win98. My program
should test the XMS-memory under DOS 7.10, so I got CWSDPMI 4.0 to
allocate up to 256 MB XMS-Ram.

There are 2 problems: First I donīt find a function to get the
greatest *physical* coherent memory block, so I use malloc() with the
method of successive approximation, to find the biggest amount by
testing if the returned pointer is valid or not. So far so bad, the
second problem: With 96 MB Ram I allocate 128 MB + 4 KB blocksize! How
can this be?

I also wonder that I can run malloc() without CWSDPMI, but only with
64 MB + 4 KB maximum blocksize. How can I allocate precise the
availible XMS-Ram?

An adjacent question is, how could I combine GNU Fortran77 0523 with
GNU C 2.81, because I have source in Fortran from another machine. The
disadvantage of GNU Fortran is the bad dokumentation and the problems
with hardware access, there is no malloc() or such thing.

BTW: I donīt know very much about the memory mangement of DOS.

Greetings, Winfried