waitUntil: Difference between revisions

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{{Command|= Comments
{{RV|type=command
____________________________________________________________________________________________


| arma |= Game name
|game1= arma1
|version1= 1.00


|1.00|= Game version
|game2= arma2
____________________________________________________________________________________________
|version2= 1.00


| Suspend execution of [[function]] or [[SQF_syntax|SQF]] based [[Script|script]] until condition is satisfied.
|game3= arma2oa
<br>
|version3= 1.50
This command will loop and call the code inside <tt>{}</tt> ''mostly'' every frame (depends on complexity of condition and overall engine load) until the [[Code|code]] returns [[true]]. The execution of the rest of the script therefore will be suspended until [[waitUntil]] condition is satisfied and the loop is aborted.
<br>
Because of this script suspension use [[spawn]] or [[execVM]] to safely execute code containing [[waitUntil]]. |= Description
____________________________________________________________________________________________


| '''waitUntil''' condition |= Syntax
|game4= tkoh
|version4= 1.00


|p1= condition: [[Code]] |= Parameter 1
|game5= arma3
|version5= 0.50


| [[Nothing]] |= Return value
|gr1= Program Flow
____________________________________________________________________________________________
 
|x1= <code>[[waitUntil]] { [[not]] [[alive]] [[player]] };</code> |= Example 1


|x2= <code>_i = 0; [[waitUntil]] { _i = _i + 1; _i >= 100 }; </code> |= Example 2
|descr= Suspends execution of [[Scheduler|scheduled]] script until the given condition satisfied.
* This command will loop and call the code inside <tt>{}</tt> '''mostly every frame''', depends on complexity of the condition and the overall engine load, until the [[Code|code]] returns [[true]]


|x3= <code>[[waitUntil]] {[[sleep]] 0.1; [[not]] [[alive]] [[player]] };</code> |= Example 3
* If the very first execution of the code returns [[true]] the command will exit immediately, therefore it will not produce any "Suspending not allowed in this context" error when used inside [[Scheduler#Unscheduled_Environment|non-scheduled]] script. For all other uses it must be executed in environment that allows [[Scheduler#Suspension|suspension]] ([[canSuspend]]), such as [[spawn]]ed or [[execVM]]ed code


|x4= An on-the-fly custom ''[[Arma_3:_Event_Handlers|event handler]]'':
* Avoid doing {{ic|[[waitUntil]] {[[time]] > 20};}} and use {{ic|[[sleep]] 20;}} instead!
<code>_myEH = ["ZoomIn"] [[spawn]] {
    [[while]] { [[true]] } [[do]] {
        [[waitUntil]] {
            [[inputAction]] ([[_this]] [[select]] 0) == 1;
        };
        [[diag_log]] [[format]] ["%1 @ %2", [[_this]] [[select]] 0, [[diag_tickTime]]<nowiki>]</nowiki>;
    };
};</code>
Although perhaps better to use [[BIS_fnc_addStackedEventHandler|onEachFrame]], depending on the application. |= Example 4
____________________________________________________________________________________________


| [[sleep]], [[uiSleep]], [[canSuspend]], [[spawn]], [[execVM]], [[while]], [[Control Structures]]|= See also
* If you can, add a [[sleep]] to the condition to save some cpu cycles {{ic|[[waitUntil]] {[[sleep]] 1; ![[alive]] [[player]]};}}


}}
{{Feature|arma3|Since Arma 3 v1.94, a ''condition'' returning anything other than [[true]] or [[false]] '''will''' result in an appropriate type error.}}


<h3 style="display:none">Notes</h3>
|pr= For some unknown reason if you have [[waitUntil]] loop active and game is '''saved/loaded''', some variables in the expression may appear undefined for a short time. As a workaround, assign expression to a variable and make sure it is defined before [[waitUntil]] checks it:
<dl class="command_description">
<code>[[waitUntil]] { [[private]] _expression {{=}} var1 && (var2 > 10); ![[isNil]] "_expression" && { _expression } };</code>
<!-- Note Section BEGIN -->


<dd class="notedate">Posted on September 20, 2013
|s1= [[waitUntil]] condition
<dt class="note">'''[[User:Killzone_Kid|Killzone_Kid]]'''
<dd class="note">In case you have more complex code inside [[waitUntil]] loop, to be on the safe side '''always''' return boolean at the end of the scope:


<code>[[player]] [[addEventHandler]] ["Fired", {
|p1= condition: [[Code]] - The expression that '''must''' return a [[Boolean]], [[true]] to finish waiting or [[false]] to continue waiting
_null = (_this [[select]] 6) [[spawn]] {
_p = [0,0,0];
[[waitUntil]] {
if ([[isNull]] _this) [[exitWith]] {[[true]]};
_p = [[getPos]] _this;
[[false]] //<-- boolean at the end of the scope
};
[[hint]] [[str]] _p;
};
}];</code>


<dd class="notedate">Posted on December 20, 2006 - 19:55
|r1= [[Anything]] - The value the condition evaluates to when the wait is over (normally [[true]])
<dt class="note">'''[[User:CrashDome|CrashDome]]'''
<dd class="note">
waitUntil suspends both SQF functions and SQF scripts. In functions, the calling script is still in suspension due to waiting for a return from the [[call]] command. The game engine will continue, however. See [[Function]] for more detail.


|x1= <code>[[waitUntil]] { [[not]] [[alive]] [[player]] };</code>


<dd class="notedate">Posted on April 2, 2010 - 17:10
|x2= <code>_i = 0; [[waitUntil]] { _i = _i + 1; _i >= 100 };</code>
<dt class="note">'''[[User:Roehre|Roehre]]'''
<dd class="note">
If WaitUntil uses an undefined [[call]] code, WaitUntil won't release, even when this code is separated from other conditions through [[or]]. Be warned that this won't cause an error message.


|x3= <code>[[waitUntil]] {[[sleep]] 1; [[not]] [[alive]] [[player]] }; {{cc|Checks every 1 second}}</code>


<dd class="notedate">Posted on Jan 07, 2011
|x4= An on-the-fly custom ''[[Arma_3:_Event_Handlers|event handler]]'':
<dt class="note">'''[[User:kju|kju]]'''
<code>_myEH = ["ZoomIn"] [[spawn]] {
<dd class="note">
[[while]] { [[true]] } [[do]] {
By default the cycle time for the condition check is per frame. Look at the example 3, how to set it at a lower rate yourself.
[[waitUntil]] {
Often times one does not need per frame checking. Saves a lot CPU checks; especially when the condition is complex to compute.
[[inputAction]] ([[Magic Variables#this|_this]] [[select]] 0) == 1;
};
[[diag_log]] [[format]] ["%1 @ %2", [[Magic Variables#this|_this]] [[select]] 0, [[diag_tickTime]]<nowiki>]</nowiki>;
};
};</code>
Although perhaps better to use [[BIS_fnc_addStackedEventHandler|onEachFrame]], depending on the application.


|x5= Use [[getVariable]] with default value to prevent unexcepted script errors:
<code>[[waitUntil]] { bank [[getVariable]] ["money", 0] > 0 };
[[waitUntil]] { [[missionNamespace]] [[getVariable]] ["isready", [[false]]] };</code>


<!-- Note Section END -->
|x6= Always return [[Boolean]]:<code>{{cc|bad}}
</dl>
[[waitUntil]] { [[if]] ([[not]] [[alive]] [[player]]) [[exitWith]] {}; _time {{=}} _time + 1 };
{{cc|good}}
[[waitUntil]] { [[if]] ([[not]] [[alive]] [[player]]) [[exitWith]] { [[true]] }; _time {{=}} _time + 1; [[false]] };
{{cc|perfect}}
[[waitUntil]] { [[not]] [[alive]] [[player]] };</code>


<h3 style="display:none">Bottom Section</h3>
|seealso= [[sleep]], [[uiSleep]], [[canSuspend]], [[spawn]], [[execVM]], [[while]], [[Control Structures]]
}}


[[Category:Scripting Commands|WAITUNTIL]]
<dl class="command_description">
[[Category:Scripting Commands ArmA|WAITUNTIL]]
[[Category:Scripting Commands ArmA2|{{uc:{{PAGENAME}}}}]]
[[Category:Scripting Commands Arma 3|{{uc:{{PAGENAME}}}}]]
[[Category:Scripting_Commands_Take_On_Helicopters|{{uc:{{PAGENAME}}}}]]


<!-- CONTINUE Notes -->
<dt><dt>
<dl class="command_description">
<dd class="notedate">Posted on December 20, 2006 - 19:55</dd>
<dt class="note">[[User:CrashDome|CrashDome]]</dt>
<dd class="note">
waitUntil suspends both SQF functions and SQF scripts. In functions, the calling script is still in suspension due to waiting for a return from the [[call]] command. The game engine will continue, however. See [[Function]] for more detail.
<dt><dt>
<dd class="notedate">Posted on April 2, 2010 - 17:10</dd>
<dt class="note">[[User:Roehre|Roehre]]</dt>
<dd class="note">
Prior to Arma 3 v1.94 if [[waitUntil]] uses an undefined [[call]] code, [[waitUntil]] won't release, even when this code is separated from other conditions through [[or]]. Be warned that this won't cause an error message.
<dt><dt>
<dd class="notedate">Posted on December 13, 2014 - 23:25 (UTC)</dd>
<dd class="notedate">Posted on December 13, 2014 - 23:25 (UTC)</dd>
<dt class="note">[[User:Commy2|Commy2]]</dt>
<dt class="note">[[User:Commy2|Commy2]]</dt>
<dd class="note">
<dd class="note">
If you want to use waitUntil together with exitWith, remember that the loop only exits if the code block returns true.<br>
If you want to use [[waitUntil]] together with [[exitWith]], remember that the loop only exits if the code block returns true.<br>
<br>
<br>
It should look like this:
It should look like this:
<code>
<code>[[waitUntil]] {
waitUntil {
{{cc|exit loop if the unit gets deleted}}
  // exit loop if the unit gets deleted
[[if]] ([[isNull]] _unit) [[exitWith]] { [[true]] }; {{cc|has to return true to continue}}
  if (isNull _unit) exitWith {true}; // has to return true to continue


  !alive _unit;
![[alive]] _unit;
};
};
</code>
</code>
</dd>


</dd>
</dl>
</dl>
<!-- DISCONTINUE Notes -->

Revision as of 16:46, 12 June 2021

Hover & click on the images for description

Description

Description:
Suspends execution of scheduled script until the given condition satisfied.
  • This command will loop and call the code inside {} mostly every frame, depends on complexity of the condition and the overall engine load, until the code returns true
  • If the very first execution of the code returns true the command will exit immediately, therefore it will not produce any "Suspending not allowed in this context" error when used inside non-scheduled script. For all other uses it must be executed in environment that allows suspension (canSuspend), such as spawned or execVMed code
Arma 3
Since Arma 3 v1.94, a condition returning anything other than true or false will result in an appropriate type error.
Problems:
For some unknown reason if you have waitUntil loop active and game is saved/loaded, some variables in the expression may appear undefined for a short time. As a workaround, assign expression to a variable and make sure it is defined before waitUntil checks it: waitUntil { private _expression = var1 && (var2 > 10); !isNil "_expression" && { _expression } };
Groups:
Program Flow

Syntax

Syntax:
waitUntil condition
Parameters:
condition: Code - The expression that must return a Boolean, true to finish waiting or false to continue waiting
Return Value:
Anything - The value the condition evaluates to when the wait is over (normally true)

Examples

Example 1:
waitUntil { not alive player };
Example 2:
_i = 0; waitUntil { _i = _i + 1; _i >= 100 };
Example 3:
waitUntil {sleep 1; not alive player }; // Checks every 1 second
Example 4:
An on-the-fly custom event handler: _myEH = ["ZoomIn"] spawn { while { true } do { waitUntil { inputAction (_this select 0) == 1; }; diag_log format ["%1 @ %2", _this select 0, diag_tickTime]; }; }; Although perhaps better to use onEachFrame, depending on the application.
Example 5:
Use getVariable with default value to prevent unexcepted script errors: waitUntil { bank getVariable ["money", 0] > 0 }; waitUntil { missionNamespace getVariable ["isready", false] };
Example 6:
Always return Boolean:// bad waitUntil { if (not alive player) exitWith {}; _time = _time + 1 }; // good waitUntil { if (not alive player) exitWith { true }; _time = _time + 1; false }; // perfect waitUntil { not alive player };

Additional Information

See also:
sleepuiSleepcanSuspendspawnexecVMwhileControl Structures

Notes

Report bugs on the Feedback Tracker and/or discuss them on the Arma Discord or on the Forums.
Only post proven facts here! Add Note
Posted on December 20, 2006 - 19:55
CrashDome
waitUntil suspends both SQF functions and SQF scripts. In functions, the calling script is still in suspension due to waiting for a return from the call command. The game engine will continue, however. See Function for more detail.
Posted on April 2, 2010 - 17:10
Roehre
Prior to Arma 3 v1.94 if waitUntil uses an undefined call code, waitUntil won't release, even when this code is separated from other conditions through or. Be warned that this won't cause an error message.
Posted on December 13, 2014 - 23:25 (UTC)
Commy2
If you want to use waitUntil together with exitWith, remember that the loop only exits if the code block returns true.

It should look like this: waitUntil { // exit loop if the unit gets deleted if (isNull _unit) exitWith { true }; // has to return true to continue !alive _unit; };