function::plpgsql::returning resultset

hi,

how can I write a plpgsql function who return the entire rows of a table?
for example, if I want to return all the lines in SELECT * FROM mytable.

it seems to be possible with a C function, but is it possible too with a
plpgsql function?

thanks a lot, it is important!
can you send me your answers on esaracco@aspasia.fr

bye