[GENERAL] How to use PQfn() in libpq library?

[Bruce YUAN]

Hi All,

How to use PQfn() in libpq library?

#include <libpq-fe.h>
PGresult *PQfn(PGconn* conn,
       int fnid,
       int *result_buf,
       int *result_len,
       int result_is_int,
       const PQArgBlock *args,
       int nargs);
Who can share a detailed example source code? Which server functions can be
executed from client?
Many thanks!

Bruce