$Screen clear: Difference between revisions
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<span class="pageSubtitle">Clear tagged and/or modified attributes in a screen</span> | <span class="pageSubtitle">Clear tagged and/or modified attributes in a screen</span> | ||
This function clears the tagged and/or modified attributes for all items in a screen. While it might be useful in some normal full-screen applications, it is probably most useful in applications that receive output from a non-full-screen source but populate a screen from that source, in order to be able to use legacy full-screen code. When the legacy code has produced an updated version of the screen, the code communicating with the external source | This function clears the tagged and/or modified attributes for all items in a screen. While it might be useful in some normal full-screen applications, it is probably most useful in applications that receive output from a non-full-screen source but populate a screen from that source, in order to be able to use legacy full-screen code. | ||
<p>When the legacy code has produced an updated version of the screen, the code communicating with the external source should probably clear the tagged and/or modified bits, just as a [[Full-screen feature#READ_SCREEN_statement|Read Screen]] statement would.</p> | |||
Under Model 204 7.8 and later, $Screen_clear is [[Calling Sirius Mods $functions|callable]]. | Under Model 204 7.8 and later, $Screen_clear is [[Calling Sirius Mods $functions|callable]]. | ||
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<td>This function always returns 1.</td></tr> | <td>This function always returns 1.</td></tr> | ||
<tr><th>scr_item</th> | <tr><th>scr_item</th> | ||
<td>The screen item in the screen for which attributes are to be cleared. This can be a variable of the form <i> | <td>The screen item in the screen for which attributes are to be cleared. This can be a variable of the form %<i>screen</I>:<I>item</i> or a [[Full-screen feature#Screen_item_name_variables|screen item name variable]] of the form :%<i>string</i>.</td></tr> | ||
<tr class="head"><th>MOD or TAG</th> | <tr class="head"><th>MOD or TAG</th> | ||
<td>Indicates the attributes to be cleared: <code>MOD</code> clears only the modified attributes and <code>TAG</code> clears only the tagged attributes. If any other value is specified, including no value, both modified and tagged attributes are cleared. | <td>Indicates the attributes to be cleared: <code>MOD</code> clears only the modified attributes and <code>TAG</code> clears only the tagged attributes. If any other value is specified, including no value, both modified and tagged attributes are cleared. | ||
Revision as of 00:45, 1 June 2017
Clear tagged and/or modified attributes in a screen
This function clears the tagged and/or modified attributes for all items in a screen. While it might be useful in some normal full-screen applications, it is probably most useful in applications that receive output from a non-full-screen source but populate a screen from that source, in order to be able to use legacy full-screen code.
When the legacy code has produced an updated version of the screen, the code communicating with the external source should probably clear the tagged and/or modified bits, just as a Read Screen statement would.
Under Model 204 7.8 and later, $Screen_clear is callable.
Syntax
[%one =] $Screen_clear(scr_item, [MOD|TAG])
Syntax terms
| %one | This function always returns 1. |
|---|---|
| scr_item | The screen item in the screen for which attributes are to be cleared. This can be a variable of the form %screen:item or a screen item name variable of the form :%string. |
| MOD or TAG | Indicates the attributes to be cleared: MOD clears only the modified attributes and TAG clears only the tagged attributes. If any other value is specified, including no value, both modified and tagged attributes are cleared.
|
Example
This code fragment clears the modified attribute for screen foo (which contains screen item bar):
%rc = $screen_clear(%foo:bar, "MOD")