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epics-base/modules/database/src/std/rec/permissiveRecord.dbd.pod
2019-10-28 01:03:12 -05:00

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#*************************************************************************
# Copyright (c) 2002 The University of Chicago, as Operator of Argonne
# National Laboratory.
# Copyright (c) 2002 The Regents of the University of California, as
# Operator of Los Alamos National Laboratory.
# EPICS BASE is distributed subject to a Software License Agreement found
# in file LICENSE that is included with this distribution.
#*************************************************************************
=title Permissive Record (permissive)
The permissive record is for communication between a server and a client. An
example would be a sequence program server and an operator interface client. By
using multiple permissive records a sequence program can communicate its current
state to the client.
B<Note this record is deprecated and may be removed in a future EPICS release.>
=recordtype permissive
=cut
recordtype(permissive) {
include "dbCommon.dbd"
=head2 Parameter Fields
The record-specific fields are described below, grouped by functionality.
=head3 Scan Parameters
The permissive record has the standard fields for specifying under what
circumstances the record will be processed. These fields are listed in
L<Scan Fields>. In addition, L<Scanning Specification> explains how these
fields are used. Since the permissive record supports no direct interfaces to
hardware, its SCAN field cannot be C<<< I/O Intr >>>.
=head3 Client-server Parameters
The client and server communicate through the VAL and watchdog flag (WFLG)
fields. At initialization, both fields are set equal to 0, which means OFF. The
server sets WFLG equal to ON when it is ready to accept a request. The client
monitors WFLG and when WFLG equals 1, the client-server action is performed (a
private matter between server and client).
When WFLG is off--when the server is busy--the client program may turn the VAL
field from OFF to ON. After the server finishes its task, it will notice that
VAL is ON and will turn both WFLG and VAL OFF and performs the requested
service.
Note that when WFLG is ON, the client program ''must not'' turn VAL to on.
=fields VAL, WFLG
=cut
field(VAL,DBF_USHORT) {
prompt("Status")
promptgroup("40 - Input")
asl(ASL0)
pp(TRUE)
}
field(WFLG,DBF_USHORT) {
prompt("Wait Flag")
pp(TRUE)
}
=head3 Operator Display Parameters
The label field (LABL) contains a string given to it that should describe the
record in further detail. In addition to the DESC field. See
L<Fields Common to All Record Types> for more on the record name (NAME) and
description (DESC) fields.
=fields LABL, NAME, DESC
=cut
field(LABL,DBF_STRING) {
prompt("Button Label")
promptgroup("80 - Display")
pp(TRUE)
interest(1)
size(20)
}
=head3 Alarm Parameters
The Permissive record has the alarm parameters common to all record types.
L<Alarm Fields> lists other fields related to a alarms that are common to all
record types.
=head3 Run-time Parameters
These fields are used to trigger monitors for each field. Monitors for the VAL
field are triggered when OVAL, the old value field, does not equal VAL.
Likewise, OFLG causes monitors to be invoked for WFLG when WFLG does not equal
OLFG.
=fields OVAL, OFLG
=cut
field(OVAL,DBF_USHORT) {
prompt("Old Status")
special(SPC_NOMOD)
interest(3)
}
field(OFLG,DBF_USHORT) {
prompt("Old Flag")
special(SPC_NOMOD)
interest(3)
}
=head2 Record Support
=head3 Record Support Routines
=head4 process
long (*process)(struct dbCommon *precord)
C<<< process() >>> sets UDF to FALSE, triggers monitors on VAL and WFLG when
they change, and scans the forward link if necessary.
=cut
}