[SQL] pl/pgsql Limits

[Najm Hashmi]

Hi All,
      As it is known that any funtion, written in pl/pgsql, can only
retrun one tuple. I am just wondering  it were true as well for function
written in C language. I need to write few function that will retrun
mulitiple rows satsifying a certain set of conditions. Where I can get
some  examples.
Tahnks in advance.
Najm