Path: utzoo!mnetor!uunet!husc6!bloom-beacon!gatech!mcnc!decvax!ucbvax!LBL.GOV!nagy%warner.hepnet
From: nagy%warner.hepnet@LBL.GOV (Frank J. Nagy, VAX Wizard & Guru)
Newsgroups: comp.os.vms
Subject: RE: set file/back
Message-ID: <880408111559.20a04094@LBL.Gov>
Date: 8 Apr 88 18:15:59 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 23

> i would like to know if someone knews a method to set file file attribute
> NOBACKUP from *inside* a program. It should be the same as SET FILE/NOBACKUP.
> I've scanned the RMS manual, but didn't find any hint how to do this.
> May be it's DEC's secret, because this piece of information is hidden in the
> directory file.

The documentation you want to look at is the I/O User's Guide, Part I
about the ACP-QIO interface for the file system.  What you want to do
is use Write Attributes to write the 32-bit file characteristics
(ATR$C_UCHAR documented on page 1-18).  The bit definitions are
documented on page 1-21 (FCNNOBACKUP is really FCH$M_NOBACKUP).
The VAX C header files ATRDEF.H defines the attribute (ATR$C...) codes,
FIBDEF.H the File Information Block and FCHDEF.H the file characteristics
bits.

The NOBACKUP flag bit is in the file characteristics longword in the
file header (not in the directory).

= Frank J. Nagy   "VAX Guru & Wizard"
= Fermilab Research Division EED/Controls
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