I got a private email from Claudio saying he already answered this
question:
http://archives.postgresql.org/pgsql-patches/2006-09/msg00285.php
I forgot I saw it, so I have added comments to the C code.
---------------------------------------------------------------------------
bruce wrote:
> Tom Lane wrote:
> > "Magnus Hagander" <mha@sollentuna.net> writes:
> > > That is part of the original open() code that Claudio did back for 8.0,
> > > so it has definitly been working since then.
> >
> > Hm, maybe best not to touch it, but still...
> >
> > > I haven't really read into
> > > the code, though... But a qiuck look doesn't show me any place wher eit
> > > does ignore O_EXCL - which combination would that be?
> >
> > What's bugging me is that 0 and O_EXCL give the same answer, and
> > O_TRUNC and O_TRUNC | O_EXCL give the same answer, but O_CREAT and
> > O_CREAT | O_EXCL give different answers, as do O_CREAT | O_TRUNC
> > and O_CREAT | O_TRUNC | O_EXCL. I'm also pretty suspicious of
> > both O_CREAT | O_EXCL and O_CREAT | O_TRUNC | O_EXCL giving the
> > same answer. However, I have no idea what the semantics are of
> > the symbols the function is mapping into, so maybe it's OK.
>
> I am CC'ing Claudio Natoli on this question about
> open.c::openFlagsToCreateFileFlags(), but in looking at the code, it
> seems OK because:
>
> o O_EXCL doesn't have any meaning unless O_CREAT is used
>
> o O_TRUNC has no meaning when O_CREAT | O_EXCL are used
> because you are guaranteed to be creating a new file
>
> Claudio, the function is here, at the top of the file:
>
> http://developer.postgresql.org/cvsweb.cgi/pgsql/src/port/open.c?rev=1.18;content-type=text%2Fx-cvsweb-markup
>
> --
> Bruce Momjian <bruce@momjian.us> http://momjian.us
> EnterpriseDB http://www.enterprisedb.com
>
> + If your life is a hard drive, Christ can be your backup. +
-- Bruce Momjian <bruce@momjian.us> http://momjian.us EnterpriseDB
http://www.enterprisedb.com
+ If your life is a hard drive, Christ can be your backup. +
