(types 4)
PostgreSQL
Object Relational DataBase Management System

型の拡張(4)
入出力関数の登録
出力関数
CREATE FUNCTION complex_in(opaque)
   RETURNS complex
   AS '/usr/local/pgsql/complex.so'
   LANGUAGE 'c';
出力関数
CREATE FUNCTION complex_out(opaque)
   RETURNS opaque
   AS '/usr/local/pgsql/complex.so'
   LANGUAGE 'c';