Re: Dynamic function execution?

On Mon, Mar 13, 2006 at 10:45:47PM -0800, Nick Johnson wrote:
> Can anyone provide me with some direction on how to write a function
> I can load into postgres that will execute a function specified by
> OID (or regproc/regprocedure) at runtime, with type safety? I've been
> able to write such a function in C, but I was unable to figure out
> how to determine the parameters that the specified function expects,
> so I can prevent calling a function that doesn't match the expected
> signature (which segfaults postgres).

Does the calling function have to be written in C? In PL/pgSQL you
could easily query pg_proc with the oid to get the called function's
name, argument types, etc., then build an appropriate string to
EXECUTE. In C you could use SearchSysCache() and SysCacheGetAttr();
search through the source code for examples of calls to those
functions with a first argument of PROCOID.

Why do you need to do this? What problem are you trying to solve?

--
Michael Fuhr