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From: daveh@cbmvax.UUCP (Dave Haynie)
Newsgroups: comp.sys.amiga
Subject: Re: Putting devices in the filename space
Message-ID: <2407@cbmvax.UUCP>
Date: Mon, 28-Sep-87 17:11:55 EDT
Article-I.D.: cbmvax.2407
Posted: Mon Sep 28 17:11:55 1987
Date-Received: Tue, 29-Sep-87 07:23:38 EDT
References: <537@rover.UUCP>
Organization: Commodore Technology, West Chester, PA
Lines: 38

in article <537@rover.UUCP>, mph@rover.UUCP (Mark Huth) says:
> Summary: Bug?? in copy command
> 
> Has anyone else run into the following bug?(limitation)
> The copy command only accepts pathnames upto some length (I think it is
> 47 characters, but don't remeber offhand)
> 
> Mark Huth

I haven't seen that one yet, but there are certainly some other limitations
in pathname length lurking in there somewhere.  Many of these may be based
on who's handling that name.  For instance, if I were to take an ARP Copy
command replacement, the arguments would have no inherent string length
limitations, as these are C-style, NUL terminated strings.  The current
AmigaDOS command was written in BCPL, and as such you'd expect a string
limitation of 255 somewhere, either as an argument limit or a command line
length limit.  BCPL strings consist of a BYTE length followed by the 
characters of that string.  Obviously if you're going to allow the empty
string, then BCPL strings can't ever get longer than 255 characters a piece.

I'm not sure what kind of limitations this has on the rest of the system,
perhaps not many (assuming most things are in C).  There's no inherent
limits on the filesystem pathname, even though BCPL strings are used.  This
is because, when you are at the Packet levels of DOS and you want to obtain
a lock, you make a packet that has a lock on the parent directory and a 
BCPL string to the file/directory you're after.  This implies a maximum
file/directory name length of 255, but these are limited much more by other
things.  Since you never really have to have more that one BCPL file name
in a string at a time, there should be no absolute limit on path names.  If
you bump up a level and use dos.library, I'm not sure what to expect.  Most
dos.library calls (e.g. Open(), Lock(), ChangeDir()) accept full path names,
but at least from C these look like C strings.  Since most programs in
are written in Assembler or C, I'd expect the most common DOS path limits to
take after the limits inherent in dos.library calls, if any.
-- 
Dave Haynie     Commodore-Amiga    Usenet: {ihnp4|caip|rutgers}!cbmvax!daveh
"The A2000 Guy"                    PLINK : D-DAVE H             BIX   : hazy
     "God, I wish I was sailing again"	-Jimmy Buffett