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<div align="center"><span style="font-size: 22pt">have.key</div>

<br />
==<br /> Introduction ==

https://web.archive.org/web/20060508040524/http://www.agigames.com/agiwiki/index.php/Have.key

The '''have.key''' command returns TRUE if the player has pressed a key. <''the the value of [[reserved variable]] [[v19]] > 0.''>

== Syntax ==

have.key()

== Remarks ==

Test commands are only valid in an <code>if</code> statement.

While this command is often described as detecting the presence of key presses, it is more accurate to state that the '''have.key''' command returns TRUE if the value of [[reserved variable]] [[v19]] > 0. 

AGI first checks v19; if it is greater than 0, it immediately returns TRUE. If not, AGI then checks the [[keyboard buffer]]; if an ASCII value is in the buffer, that value is copied to v19, and then '''has.key''' returns TRUE. If no ASCII value is found in the buffer, '''have.key''' returns FALSE.
Only ASCII values will trigger the '''have.key''' command; scan codes (such as function keys or ALT key combos) will not. Also, AGI does not reset the value of v19 after calling '''have.key'''; it will continue to return TRUE until v19 is reset to zero at the beginning of the next [[AGI Interpreter Cycle|interpreter cycle]] (or if reset manually by logic code).

If you manually assign a non-zero value to v19 prior to calling the '''have.key''' command, it will return TRUE even though no key was actually pressed.

This statement can be combined with the <code>NOT</code> operator to test for no keys having been pressed.

== Possible Errors ==

When calling '''have.key''' as part of a loop to wait for a key-press, you should first reset the value of v19 to zero, in case there is already a key-press recorded in the current [[AGI Interpreter Cycle|interpreter cycle]].

== Example ==

<div class="CodeBlockHeader">Code:</div>
<syntaxhighlight lang="agi">
[ a simple loop to check for keyboard activity
v19 = 0;     [ clear the key value before starting the loop
StartLoop:
if(!have.key())
  {
  goto(StartLoop);
  }
</syntaxhighlight>

== Technical Information ==

{| border="1" cellpadding="2"
| style="background-color: #efefef" width="200" | '''Required Interpreter Version:'''
| width="175" | Available in all AGI versions.
|-
| style="background-color: #efefef" | '''Byte-Code Value:'''
| 13 (0x0D hex)
|}

==<br /> References ==

<references />

==<br /> Related Links ==

* [[AGI Command Reference - Test Commands|Test Commands]]
* [[Player Input Commands]]
* [[Keyboard Input]]
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