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From: hp@vmars.tuwien.ac.at (Peter Holzer)
Newsgroups: comp.os.msdos.programmer
Subject: Re: HELP!! Turbo-C++ FAR POINTERS
Message-ID: <1786@tuvie>
Date: 31 Aug 90 10:18:31 GMT
References: <0093BF75.AA852DC0@EA.USL.EDU>
Sender: news@tuvie
Lines: 40

johnson@EA.USL.EDU writes:

>I was trying to use a very large array (char  lines[1000][150];) using
>Turbo-C++ on a 80-x86 based pc.  I realized I needed a particular type
>of pointer to address this thing, so I used a FAR pointer.  However,
>I did something wrong and real quickly compromised the integrity of the
>FAT file on the hard-drive.  (not very fun, I couldn't even boot up)

>Needless to say I don't want to do this again.  How can I declare and
>address this array?

I don't know about TC++, but in TC 2.0, you cannot declare such an array,
you have to farmalloc it at run time. To address it you need a huge *,
not a far * (Far pointer arithmetic wraps around after 64k).

If you want your program to be 
a)	fast
	and
b)	portable to other compilers/systems,
leave the near, far, huge stuff out use the following code fragment:

--------------------------------------------------------------------
char	** lines;
int	i;

lines = malloc (1000 * sizeof (char *));
assert (lines);

for (i = 0; i < 1000; i ++) {
	lines [i] = malloc (150);
	assert (lines [i]);
}
--------------------------------------------------------------------

(This should really go into a FAQ list, the question is asked every few weeks)
--
|    _	| Peter J. Holzer			| Think of it	|
| |_|_)	| Technische Universitaet Wien		| as evolution	|
| | |	| hp@vmars.tuwien.ac.at			| in action!	|
| __/  	| ...!uunet!mcsun!tuvie!vmars!hp	|     Tony Rand	|