title: Call PostgreSQL function with multiple composite output parameters
body: <p>I'd like to define a function in PostgreSQL 9.1 that takes multiple INOUT parameters of composite types, but I don't know how to call it.</p>
  
  <p>Eg.</p>
  
  <pre><code>CREATE TYPE my_type_a AS (a integer, b float);
  CREATE TYPE my_type_b AS (c boolean, d varchar(5));
  
  CREATE FUNCTION my_complex_func(INOUT a my_type_a, INOUT b my_type_b)
  RETURNS RECORD
  '...'
  LANGUAGE plpgsql;
  </code></pre>
  
  <p>The definition statements execute just fine, but I don't know how to call this function! I tried:</p>
  
  <pre><code>SELECT INTO a, b
      a, b FROM my_complex_func(a, b);
  </code></pre>
  
  <p>but this gives an error:</p>
  
  <pre><code>ERROR:  record or row variable cannot be part of multiple-item INTO list
  </code></pre>