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af5d6b4ef6
newly-updated SGML reference pages, so I just inserted a comment that they are obsolete. If you want to transcribe the newer info into these pages, be my guest.
49 lines
1.5 KiB
Plaintext
49 lines
1.5 KiB
Plaintext
.\" This is -*-nroff-*-
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.\" XXX standard disclaimer belongs here....
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.\" $Header: /cvsroot/pgsql/src/man/Attic/listen.l,v 1.9 1998/10/08 01:16:17 tgl Exp $
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.TH "LISTEN" SQL 03/12/94 PostgreSQL PostgreSQL
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.SH NAME
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listen - listen for notification on a relation
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.SH SYNOPSIS
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.nf
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\fBlisten\fR class_name
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.fi
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.SH DESCRIPTION
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This man page is obsolete. More complete and reliable info is
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available in the User's Guide reference page for LISTEN.
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.PP
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.BR listen
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is used to register the current backend as a listener on the relation
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.IR class_name .
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When the command
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.BI notify " class_name"
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is called either from within a rule or at the query level, the
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frontend applications corresponding to the listening backends
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are notified. When the backend process exits, this registration
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is cleared.
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.PP
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This event notification is performed through the Libpq protocol
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and frontend application interface. The application program
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must call the routine
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.IR PQnotifies
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in order to find out the name of the class to which a given
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notification corresponds. If this code is not included in
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the application, the event notification will be queued and
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never be processed.
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.PP
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Note that
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.IR class_name
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needs not to be a valid class name but can be any ascii string up to 32
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characters long. It must however be eclosed in double-quotes if it is
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not valid as class name.
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.SH "SEE ALSO"
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create_rule(l),
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notify(l),
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select(l),
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unlisten(l),
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libpq.
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.SH BUGS
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The
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.IR psql(1)
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command does not poll for asynchronous events.
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