Subject:	Re: ls (of filutl32)
To:	ericb AT lsid DOT hp DOT com (Eric Backus)
Date:	Tue, 13 Oct 92 13:17:18 EDT
From:	Stephen Turnbull <turnbull AT ecolan DOT sbs DOT ohio-state DOT edu>
Sender:	turnbull AT ecolan DOT sbs DOT ohio-state DOT edu

Chris and Eric are noting anomolies in MS-DOS directory listings.  I
haven't actually gotten into directory code in a major way since I
retired my Osborne 1 and CP/M, but I have some suspicions from looking
at Zortech C++'s directory classes and DOS interface function
descriptions:

> It sounds like you are using go32 to do wild-card expansion.  The
> expansion that go32 does is MS-DOS style, which means that "*" doesn't
> match a filename that has a "." in the middle of it (you need "*.*" to
> match all files).  MS-DOS style expansion also means that anything
> after a "*" is ignored, so that "ls *test.c" is equivalent to "ls
> *.c".  Also, for reasons that I don't understand, a "*" gets expanded
> to include both "." and "..", which is what you are seeing.  This
> seems wrong to me, but it's in go32 or maybe is built into MS-DOS and
> is therefore out of my hands.

If I remember correctly, "." and ".." are not entries in an MS-DOS
directory.  MS-DOS finds them by special casing them.  Inconsistently
enough, the special case considers them to be alphabetical.  That's
MS-DOS; not much you can do about it ;-)
    I don't know about GO32 or COMMAND.COM, but under 4DOS "*" is
equivalent to "*.*"; to get the behavior you describe you need "*.".
4DOS also accepts the "*test.c" syntax.

> On a related note, I've noticed some strangeness even with "noglob" in
> my GO32 environment variable.  For example, if I do "ls *~" to list my
> emacs backup files, this works correctly if there is at least one
> backup file (because the shell expands "*~" into a list of file names
> before ls even sees it).  But if there aren't any backup files,
> something is expanding the "*~" into "." or something like that.  This
> behavior seems wrong, but I don't know how to fix it.  I assume the
> cause is some low-level MS-DOS call which is doing wild-card
> expansion.  Or maybe go32.exe is doing this even though noglob is set.

In csh, "~" is an abbreviation for $HOME.  Since MS-DOS doesn't know
about it, it sounds like either "ls" or "MS_SH200" is globbing "*~",
and for some reason when it doesn't find anything else, tries "~" as a
special case and gets $HOME or maybe ".".  I don't think that
low-level MS-DOS functions do any globbing; that's all done by the
user program.  Most libraries have slightly higher-level functions
which do some globbing, but the entries to DOS via INT 21 insist that
only single character wildcards ("?") are permitted.
--
Stephen Turnbull    The Ohio State University    Department of Economics
      410 Arps Hall, 1945 N. High St., Columbus, OH 43210-1172 USA 
  Phone: (614) 292-0654    Fax: ...-3906    Email: turnbull DOT 1 AT osu DOT edu

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