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understanding Datum -> char * -> Datum conversions

From: Louis-David Mitterrand <cunctator(at)apartia(dot)ch>
To: pgsql-hackers(at)postgresql(dot)org
Subject: understanding Datum -> char * -> Datum conversions
Date: 2000-05-24 16:26:41
Message-ID: 20000524182641.A6621@styx (view raw or flat)
Thread:
Lists: pgsql-hackers
Hello,

I am learning to programm triggers in C by using the examples and the
programmer's manual but it's a steep learning curve for a mere perl
programmer ;-)

What I am trying to do for instance is:
- read a ::text colum with SPI_getbinval(),
- convert it to a char*,
- modify it,
- convert it back to a Datum,
- reinsert it into the tuple through SPI_modifytuple,

The conversions involve some pointer magic and casting that I really
don't grasp.

Also I am trying to read a timestamp with SPI_getbinval and get the
number of seconds contained. Using DatumGetInt32 doens't seem to do it.

Thanks in advance for your insight, cheers,

-- 
Louis-David Mitterrand - ldm(at)apartia(dot)org - http://www.apartia.fr

Radioactive cats have 18 half-lives.

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Subject: Re: understanding Datum -> char * -> Datum conversions
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