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<h1 class="topictitle1">CLRL (Clear Line) keyword for display files</h1>
<div><p>Use this record-level keyword to specify that the <span class="keyword">i5/OS™</span> operating
system is to clear (delete) a specific number of lines before the record is
displayed. Only those lines are cleared. </p>
<div class="section"> <div class="note"><span class="notetitle">Note:</span> As with OVERLAY, other records remain on the display.</div>
<p>See
the <a href="../books/sc415715.pdf" target="_blank">Application
Display Programming book</a><img src="wbpdf.gif" alt="Link to PDF" /> for information about how to use CLRL in files that are used in the System/36™ environment.</p>
<p>The
format of the keyword is:</p>
<pre>CLRL(nn|*END|*NO|*ALL)</pre>
<p>You
can specify the CLRL keyword in one of the following ways:</p>
<ul><li>Specify nn, where nn is an integer between 1 and 27. The number specified
is the number of lines cleared, starting with and including the first line
on which the record is to be displayed. If the SLNO (Starting Line Number)
keyword is also specified for this record format, the clearing of lines begins
with the starting line number in effect for the record format at the time
it is displayed. <div class="note"><span class="notetitle">Note:</span> When specifying nn, the record must have at least one
field defined.</div>
</li>
<li>Specify *END to indicate that all lines starting with and including the
first line on which the record is to be displayed are to be cleared. For a
24 x 80 display, lines up to and including line 24 are cleared. For a 27 x
132 display, lines up to and including line 27 are cleared.</li>
<li>Specify *NO so that no lines on the display are cleared before displaying
the record whose format you are defining. The displayed record overlays any
data already on the display.</li>
<li>Specify *ALL so that all of the lines on the display are cleared before
displaying the record whose format you are defining. At least one field must
be defined in the record format.</li>
</ul>
<p>When a record format begins with a field in position 1, the beginning
attribute byte of the format is in the last position of the previous line.
The previous line number is the starting line number in the format. This also
applies to a SLNO format with a field defined in the DDS in line 1, position
1.</p>
<p>If the record format for which the CLRL keyword is specified has
one or more input-capable fields, any records that are overlaid are no longer
recognized by the <span class="keyword">i5/OS</span> operating
system. That is, any input-capable fields can no longer be typed into, any
input operation written to one of those records results in an error, and they
cannot be cleared by selecting the ERASE keyword.</p>
<p>If you specify the
CLRL(nn) keyword in a record format without input-capable fields, the input-capable
fields in the overlapped records remain input-capable. That is, input-capable
fields in the overlaid records remain input-capable, and input operations
written to those record formats are still valid. If the ROLLUP or ROLLDOWN
keywords are specified on the record containing the CLRL keyword, they are
ignored. Records with the CLRL keyword and no input-capable fields are not
cleared properly when they are overlaid by other records that have the OVERLAY
keyword specified. The lines needed for the overlapping record are cleared
and the lines not needed for the overlapping record remain on the display.</p>
<p>You
can use the CLRL(*NO) keyword to prevent an overlapped record from being cleared
when the overlapping record is written to the display. If you use this keyword,
any records being displayed that are to be overlapped are not cleared from
the display. The new record overlays them entirely or partially. There is
a performance advantage to using CLRL(*NO) if you have a display containing
constants and data that is repeatedly sent to the display. Sending constants
as a separate format and using the CLRL(*NO) keyword for the format containing
the data reduces the time required to send the record format to the display.</p>
<p>If
the CLRL keyword is not specified and neither OVERLAY nor PUTOVR (Put with
Explicit Override) is specified, the entire display is cleared.</p>
<p>If
the CLRL keyword is used and the PUTOVR or PUTRETAIN keyword is in effect,
the clearing of any lines might conflict with the PUTOVR or PUTRETAIN function.
The PUTOVR or PUTRETAIN keyword requires that the fields being overridden
be on the display, while the CLRL(nn) or CLRL(*END) keyword clears those fields
first. If a record becomes unavailable for input because of the CLRL(nn) or
CLRL(*END) keyword, the input-capable fields remain input-capable if the PUTOVR
keyword is in effect. However, the <span class="keyword">i5/OS</span> operating
system sends a message if the program attempts to read such a record.</p>
<p>If
you specify the CLRL keyword, you should also specify RSTDSP(*YES) on the
Create Display File (CRTDSPF) or Change Display File (CHGDSPF) command. Otherwise,
data on the display can be lost if the file is suspended.</p>
</div>
<div class="section"><h4 class="sectiontitle">Prevent overlapped records from being cleared</h4><p>The
CLRL keyword cannot be specified with any of the following keywords:</p>
<div class="tablenoborder"><table cellpadding="4" cellspacing="0" summary="" width="100%" frame="void" border="0" rules="none"><tbody><tr><td valign="top" width="50%"><p>ASSUME<br />
KEEP<br />
SFL</p>
</td>
<td valign="top" width="50%"><p>SFLCTL<br />
USRDFN</p>
</td>
</tr>
</tbody>
</table>
</div>
<p>A warning message appears at file creation time if the CLRL keyword
is specified on a record with the DSPMOD keyword. At run time, the CLRL keyword
is ignored when the display mode changes.</p>
<p>The CLRL keyword cannot be
specified for the record format specified by the PASSRCD keyword.</p>
<p>Option
indicators are not valid for this keyword.</p>
</div>
<div class="example"><h4 class="sectiontitle">Example</h4><p>The following example shows how to specify
the CLRL keyword.</p>
<pre>|...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+....8
00010A R RECORD1 CLRL(5)
00020A FLD1 5 3 2
00030A FLD2 10 OB 5 2
00040A FLD3 10 I 6 2
00050A*
00060A R RECORD2 CLRL(*NO)
00070A FLD1 5 2 2 2
00080A FLD2 5 H
00090A FLD3 10 I 4 2
00100A*
00110A R RECORD3 CLRL(*END)
00120A FLD1 5 B 5 2
00130A FLD2 5 I 8 2
A</pre>
<p>Lines 3, 4, 5, 6, and 7 are cleared before RECORD1 is
displayed. In RECORD2, no lines are cleared, and when the record is displayed,
it will overlay anything already displayed. Lines 5 through 24 are cleared
before RECORD3 is displayed.</p>
</div>
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<div class="familylinks">
<div class="parentlink"><strong>Parent topic:</strong> <a href="rzakcmstkeyent.htm" title="You type the keyword entries that define display files in positions 45 through 80 (functions).">DDS keyword entries for display files (positions 45 through 80)</a></div>
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