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Date:	Sat, 27 Oct 2001 20:52:20 -0400 (EDT)
From:	Charles Wilson <cwilson AT ece DOT gatech DOT edu>
X-X-Sender:	cwilson AT medulla DOT ibb DOT gatech DOT edu
To:	Goksun Ilhan <goksun_ilhan AT yahoo DOT com>
cc:	cygwin AT cygwin DOT com
Subject:	Re: Perl database problem
In-Reply-To:	<20011026225958.19008.qmail@web10804.mail.yahoo.com>
Message-ID:	<Pine.GSO.4.40.0110272048050.27218-100000@medulla.ibb.gatech.edu>
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On Fri, 26 Oct 2001, Goksun Ilhan wrote:
> I am trying to run a Perl program in cygwin. When I
> create the database using dbmopen command, it looks
> like it's working (it's only creating .pag file, not
> .dir file). However, when I try to read something from
> the database, it cannot open the file. I run the
> program on a UNIX machine and it works. Is there way
> to run that program using cygwin?

cygwin's perl uses gdbm to provide back end database services (including
NDBM:: GDBM:: and ODBM::).  The dbmopen() command that you reference
indicates that you are using the NDBM:: flavor.  When gdbm is used in its
ndbm-emulation mode, it stores the data in the .pag file -- but creates a
.dir file as a HARD LINK so that the on-disk footprint of this
gdbm-masquerading-as-ndbm is the same as REAL ndbm databases.

However, hard links don't work on FAT drives, only NTFS drives.  (No, we
can't change gdbm to use symlinks instead -- the hard link is necessary
because REAL ndbm expects both files to have the same timestamp.  With
hardlinks, they will.  with symlinks, they won;t).

Solution?  Don't use ndbm.  (NDBM::)  Use gdbm.

Or, make sure your databases are created on an NTFS drive.

--Chuck



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