From: niklas | brueckenschlaeger <niklas@...>
Date: 2010-11-17T07:07:40+09:00
Subject: Re: File#truncate fills file with zeros

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this is because opening a file with "w" truncates it.

On Wed, 2010-11-17 at 06:33 +0900, Leslie Viljoen wrote:
> Hello!
>=20
> Running this following code:
>=20
> f =3D File.open(filename, 'w')
> f.truncate(10)
> f.close
>=20
> leaves the file filled with 10 zero bytes. Its pretty unexpected,
> since the documentation makes no mention of this
> (http://ruby-doc.org/core/classes/File.html#M002539).
>=20
> File.truncate(filename, 10)
>=20
> works fine, leaving any pre-existing bytes intact. Looking at the
> example I assume this has to do with the File#truncate method
> expecting me to write some bytes and then truncate them.
>=20
> Just putting this out there for the next confused person since Google
> made no mention of this!
>=20


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