cannot create a user defined function

[mberrada]

Hi guys,
I am trying to follow this: http://www.postgresql.org/docs/9.2/static/xtypes.html
to learn how to create new functions and datatypes. But I keep getting error for the CREATE FUNCTION because of the "filename" portion. I get the error: could not access file . filename: no such file or directory.

I am not actually sure on what goes on the "filename". I tried the folder where they are defined: postgresql-9.2.3/src/backend/utils/adt' or the file name itself geo_ops.c (that's where my functions are defined).

It says that I have to have it compiled and loaded but I thought that this was automatically done since geo_ops is already part of the source code. Any help please???

[rski]

Is it written

Once we have written the I/O functions and compiled them into a shared library
 

You have to compile code into shared library

[mberrada]

yes, you are right! But this is actually my problem. I am apperently not able to compile it into shared library
so when I go to the postgres folder, and try this command:
cc -fpic -c src/backend/utils/adt/geo_ops.c
I get this error:
fatal error: postgres.h: No such file or directory

I really don't understand why. I read many articles about how to compile into a shared lib and they all suggest the same thing...
(this is the article I am using http://www.postgresql.org/docs/7.1/static/xfunc-c.html and I am using a linux machine)
Thanks