Re: SPI question (or not): trying to read from Large Objects from within a function - Mailing list pgsql-general

From David Helgason
Subject Re: SPI question (or not): trying to read from Large Objects from within a function
Date
Msg-id 7F6484AA-40D1-11D8-BF3E-000A9566DA8A@uti.is
Whole thread Raw
In response to Re: SPI question (or not): trying to read from Large Objects from within a function  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: SPI question (or not): trying to read from Large Objects from within a function  (David Helgason <david@uti.is>)
List pgsql-general
Thank you very much,

I figured I needed to open my own using SPI_connect(). I had assumed
that there was sth like a
the-connection-this-functions-is-begin-run-through.

Now I'm having problems with

size_t inBufSize = 8192;
char* inBuffer = (char*)palloc(inBufSize);
int bytes_read = DatumGetInt32(DirectFunctionCall3(loread,
Int32GetDatum(fd), CStringGetDatum(inBuffer),
UInt32GetDatum(inBufSize)));

which returns an extremely large number in bytes_read (consistently
46235672), regardless of the contents of inBufSize.

I tried using lo_lseek(fd, 0, SEEK_END) on this fd already, which
correctly returned the size of the Large Object, so it's not a question
of an invalid descriptor. Also that seek didn't effect the result at
all. I guess it's wrong usage of the DatumGet*() / *GetDatum()
functions, but I can't see where.

Any suggestions?

d.

On 7. jan 2004, at 05:40, Tom Lane wrote:

> David Helgason <david@uti.is> writes:
>> I'm having trouble finding out how to find the current PGconn
>> connection inside a C function.
>
> What makes you think that "*the* current PGconn" is a valid concept?
> libpq has always supported multiple active connections.
>
>             regards, tom lane
>
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