Re: [GENERAL] Geometric, getting x and y co-ordinates GOING MAD!!!!!

Following my original posting, I did a bit of hunitng in the source and
used them to come up with these functions:

/* get_x.c
a function to return the x coord of a point */

#include "postgres.h"
#include "utils/geo_decls.h"

double
get_x(Point *pt)
{
if (!PointerIsValid(pt))
return NULL;

return pt->x;
} /* get_x() */

/* get_y.c
a function to return the y coord of a point */

#include "postgres.h"
#include "utils/geo_decls.h"

double
get_y(Point *pt)
{
if (!PointerIsValid(pt))
return NULL;

return pt->y;
} /* get_y() */

... then I do ...

cc -c get_<x|y>.c -I/usr/local/pgsql/include
ld -G -Bdynamic -o get_<x|y>.so get_<x|y>.o

which gives me get_x.so and get_y.so

... then I do (within psql)...

brecard10=> CREATE FUNCTION get_<x|y>(point) RETURNS float
brecard10-> AS '/usr/people/postgres/get_<x|y>.so' LANGUAGE 'c';

AND NOW FOR THE CRAZY PART...

brecard10=> select * from points;
id|pos
--+-----------
1|(1,2)
2|(-1.3,4.77)
3|(0,-3)
(3 rows)

brecard10=> select id,pos,get_x(pos) from points;
id|pos |get_x
--+-----------+-----
1|(1,2) | 1
2|(-1.3,4.77)| -1.3
3|(0,-3) | 0
(3 rows)

Rejoice I thought, I'm a genius, wealth, power and good looks will soon
follow...

brecard10=> select id,pos,get_y(pos) from points;
id|pos |get_y
--+-----------+-----
1|(1,2) | 1
2|(-1.3,4.77)| -1.3
3|(0,-3) | 0
(3 rows)

There goes the nobel, my seat in the parliament and my winning smile!

I have no training in C so I've reached this far by trial and error. I
have however discovered that if write a function such as

/* pants.c
weird of what! */
#include "postgres.h"
#include "utils/geo_decls.h"
double
pants(Point *pt)
{
return 2.0;
}

and compile it as above and make it a function I get:

brecard10=> select id,pos,pants(pos) from points;
id|pos |pants
--+-----------+-----
1|(1,2) | 1
2|(-1.3,4.77)| -1.3
3|(0,-3) | 0
(3 rows)

HELP!
WHAT'S GOING ON!!!
Why can't I get to pt->y?
Why does function pants behave just like get_x (and get_y)?

Stuart.
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| Stuart Rison | Ludwig Institute for Cancer Research |
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| Tel. (0171) 878 4041 | London, W1P 8BT, UNITED KINGDOM. |
| Fax. (0171) 878 4040 | stuart(at)ludwig(dot)ucl(dot)ac(dot)uk |
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