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From: wescott@sauron.UUCP
Newsgroups: comp.unix.wizards
Subject: Re: BSD to SysV
Message-ID: <942@sauron.Columbia.NCR.COM>
Date: Wed, 28-Oct-87 18:19:26 EST
Article-I.D.: sauron.942
Posted: Wed Oct 28 18:19:26 1987
Date-Received: Sat, 31-Oct-87 11:04:44 EST
References: <9940@brl-adm.ARPA> <31892@sun.uucp> <1596@u1100a.UUCP>
Reply-To: wescott@sauron.Columbia.NCR.COM (Mike Wescott)
Organization: Entry Level Systems Development, NCR Corp., Columbia, SC
Lines: 20

In article <1596@u1100a.UUCP> dbg@u1100a.UUCP (D B Grooms) writes:
 >> Has anyone figured out how to perform the BSD functions ``fsync()''
 >> and ``ftruncate()'' in System V?
  
 >>>... making a copy of the file up to the new length, doing a "creat" or
 >>>"open" with O_TRUNC to truncate the original file to zero length, and then
 >>>copying the truncated copy on top of the original file.
 
 > For efficiency, it would be better to "mv" the original file to one with a 
 > new name, "creat" the original file, and copy the desired size from the 
 > newly named file to the original.  This involves only one copy operation
 > instead of two.

This does not take care of links and is not a general solution.  Any other
name for the original file remains linked to the original inode and is not
truncated.

-- 
	-Mike Wescott
	 wescott@ncrcae.Columbia.NCR.COM