Re: Shortening an IFS file

[MichaelQuigley@xxxxxxxxxx]

So do you open the file without o_Trunc, read the data in, close the file, 
open it with o_Trunc, process the data already read, and write the 
modified data back out? When the file is opened with o_Trunc, it wipes out 
the existing data before it can be read. (Unless I've done something wrong 
or simply don't understand.)

"MIDRANGE-L" <midrange-l-bounces@xxxxxxxxxxxx> wrote on 03/12/2015 
10:14:08 AM:

> From: Tim Brown <tim.bronski@xxxxxxxxx>
> To: Midrange Systems Technical Discussion <midrange-l@xxxxxxxxxxxx>
> Date: 03/12/2015 10:14 AM
> Subject: Re: Shortening an IFS file
> Sent by: "MIDRANGE-L" <midrange-l-bounces@xxxxxxxxxxxx>
>
> I might have read your email too quickly. If you want to clear the 
contents
> of a file before writing back to it then use the open option i 
suggested.
> If you want to keep the contents up to a particular size then use 
ftruncate.
> On Mar 12, 2015 2:40 PM, "Tim Bronski" <tim.bronski@xxxxxxxxx> wrote:
>
> > If you're using open() then you should have O_TRUNC or'ed as a flag.
> >
> > On 3/12/2015 2:32 PM, MichaelQuigley@xxxxxxxxxx wrote:
> >
> > > I'm writing a utility to remove some filler data from an IFS file. 
I'm
> > > using the  The utility works great except that when I write the data 
back
> > > to the IFS, there is original data past where I want the new EOF to 
be. I
> > > can't for the life of me figure out how to shorten the file and set a 
new
> > > (shorter) end of file.
> > >
> > > Any help would be greatly appreciated.
> > >
> > > Thanks,
> > > Michael Quigley
> > > Computer Services
> > > The Way International
> > > www.TheWay.org
> >
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