Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!ucla-cs!ucla-ma!terry
From: terry@joshua.math.ucla.edu
Newsgroups: comp.lang.c
Subject: need help with large arrays & Turbo C
Message-ID: <1991Jun14.013524.7243@math.ucla.edu>
Date: 14 Jun 91 01:35:24 GMT
Sender: terry@MATH.UCLA.EDU
Reply-To: terry@MATH.UCLA.EDU ()
Distribution: na
Organization: UCLA Mathematics Department
Lines: 46

Help!  I am having trouble porting a program from Microsoft C 5.x (I think)
to Turbo C 2.0.

The problem concerns some arrays.  In the MSC source, they are defined in
one module as

	unsigned huge buf[131072]
	float huge difbuf[32][1024]

In the headers of the other source files, the variables are referred to as

	extern unsigned huge buf[]
	extern float huge difbuf[32][1024]

This has to be compiled with the medium memory model.

Turbo C has two complaints:

	1. The arrays are too big (each is bigger than one segment)
	2. "huge" can only modify pointers, not arrays

It seems that with Turbo C, I have to declare something like

	unsigned huge *buf
	buf = farmalloc(131072L * sizeof(unsigned))

and in the other files put

	extern unsigned huge *buf

Now, according to the FAQ, *buf and buf[] are not quite the same; I'm
afraid I am making some mistake in the extern definition.  However, I want
to keep the 'huge' modified in there to beware of pointer arithmetic.

I'm entirely unsure what to do with the 2D array, difbuf.

And lastly, I want to initialize these arrays with memset(), but memset()
only sets up to 65535 elements.  The arrays may change in size; is there a
good way to figure the size at run time and initialize with several calls
to memset()?

Please help!  Please send your replies by e-mail; I will post a summary.

Thanks!

terry