set persistent search_path

Greetings,

I created a user with read-only access to a schema of another user. My
functions work with anonymous tables (I mean, there is no prefix of the
schema), and when I invoke those functions, I got errors about not
knowing the relations (tables).

How can I change the search_path in a persistent way for a read-only
user that not owns the schema, to avoid set it in every session?

I even don't know if the set search_path works at run-time, but even
with that, it's annoying put it on the top of each function...

thanks,
Pedro Salazar.
-- 
PS
pedro-b-salazar@ptinovacao.pt
PGP:0E129E31D803BC61