<primary>trigger</primary>

</indexterm>

<indexterm zone="datatype-pseudo">

<primary>event_trigger</primary>

</indexterm>

<indexterm zone="datatype-pseudo">

<primary>pg_ddl_command</primary>

</indexterm>

<indexterm zone="datatype-pseudo">

<primary>language_handler</primary>

</indexterm>

<row>

<entry><type>record</></entry>

<entry>Identifies a function returning an unspecified row type.</entry>

<entry>Identifies a functiontaking orreturning an unspecified row type.</entry>

</row>

<row>

<entry><type>trigger</></entry>

<entry>A trigger function is declared to return <type>trigger.</></entry>

</row>

<row>

<entry><type>event_trigger</></entry>

<entry>An event trigger function is declared to return <type>event_trigger.</></entry>

</row>

<row>

<entry><type>pg_ddl_command</></entry>

<entry>Identifies a represention of DDL commands that is available to event triggers.</entry>

</row>

<row>

<entry><type>void</></entry>

<entry>Indicates that a function returns no value.</entry>

<para>

Functions coded in procedural languages can use pseudo-types only as

allowed by their implementation languages. At presentthe procedural

languagesallforbid use of a pseudo-type as argument type, and allow

allowed by their implementation languages. At presentmost procedural

languages forbid use of a pseudo-type as an argument type, and allow

only <type>void</> and <type>record</> as a result type (plus

<type>trigger</> when the function is used as a trigger). Some also

<type>trigger</> or <type>event_trigger</> when the function is used

as a trigger or event trigger). Some also

support polymorphic functions using the types <type>anyelement</>,

<type>anyarray</>, <type>anynonarray</>, <type>anyenum</>, and

<type>anyrange</>.