From: Tom Lane <tgl@sss.pgh.pa.us>
To: Jeroen T. Vermeulen <jtv@xs4all.nl>
Cc: Stephane Raimbault <stephane.raimbault@free.fr>
Cc: pgsql-interfaces@postgresql.org
Subject: Re: libpq 7.4 and binary cursor
Date: Thu, 10 Jun 2004 11:39:25 -0400
Message-ID: <25064.1086881965@sss.pgh.pa.us> (raw)
In-Reply-To: <20040610150411.GD27490@xs4all.nl>
References: <1086877827.4646.22.camel@picasso.lan>
<20040610150411.GD27490@xs4all.nl>
"Jeroen T. Vermeulen" <jtv@xs4all.nl> writes:
> This trick may work on some compilers and/or platforms, but it's not
> correct C. The language does not guarantee that the members of a union
> will be allocated in the exact same address, or even that they will
> overlap.
Nonsense. C99 6.7.2.1:
A pointer to a union object, suitably converted, points to
each of its members (or if a member is a bit-field, then to
the unit in which it resides), and vice versa.
It does say that the results of fetching a union member other than
the one last stored to are implementation-dependent, but not that
the implementation can choose to put them in different places.
regards, tom lane
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To: pgsql-interfaces@postgresql.org
Cc: tgl@sss.pgh.pa.us, jtv@xs4all.nl, stephane.raimbault@free.fr
Subject: Re: libpq 7.4 and binary cursor
In-Reply-To: <25064.1086881965@sss.pgh.pa.us>
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