call: Difference between revisions

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


| ofpr |= Game name
|game1= ofp
|version1= 1.85


|1.85|= Game version
|game2= ofpe
|version2= 1.00


|arg= local |= Arguments in MP
|game3= arma1
|version3= 1.00


|eff= local |= Effects in MP
|game4= arma2
____________________________________________________________________________________________
|version4= 1.00


| Executes the '''function string'''.
|game5= arma2oa
|version5= 1.50


Argument(s) (if any) are passed as _this. (Argument'''s''' are passed in an array) |= Description
|game6= tkoh
____________________________________________________________________________________________
|version6= 1.00


| Argument(s) '''call''' "function string" |= Syntax
|game7= arma3
|version7= 0.50


|p1= Argument(s): [[Any Value]] - Optional. Argument that is passed to the function in the "_this" variable. |= Parameter 1
|gr1= Program Flow


|p2= function string: [[String]] - A function body provided directly 'inline' or
|descr= Adds given set of compiled instructions to the current stack and waits for it to finish and return, provides an option to pass arguments to the executed [[Code]].
the [[String]] returned from the commands [[loadFile]] or [[preprocessFile]].
See [[Scheduler]] to learn more about how the code is executed and behaves.


|s1= [[call]] code


| [[Any Value]] -
|p1= code: [[Code]] - [[compile]]d instructions
The last value given in the function is returned. See the topic [[Function]] for more information. |= Return value
{{Feature|ofp|{{ofp}} takes [[String]].}}
____________________________________________________________________________________________
{{Feature|informative|This way of calling has access to its parent scope's <sqf inline>_this</sqf>, as all it does is creating a scope.}}
 
|x1= ''[[:Category:Operation Flashpoint|Operation Flashpoint]] syntax:''
<code>_fAdd <nowiki>=</nowiki> loadFile "add.sqf"
[1,2] call _fAdd</code>


''[[:Category:Armed Assault|Armed Assault]] syntax:''
|r1= [[Anything]] - the last value given in the function is returned - see the topic [[Function#Return_Values|Function]] for more information
<code>_fAdd <nowiki>=</nowiki> [[compile]] loadFile "add.sqf"
_result <nowiki>=</nowiki> [1,2] call _fAdd</code> |= Example 1
____________________________________________________________________________________________


| [[call_code|call code]], [[spawn]], [[compile]], [[preprocessFile]] |= See also
|s2= args [[call]] code


}}
|p21= args: [[Anything]] - arguments that are passed to the function in the <sqf inline>_this</sqf> variable.
 
|p22= code: [[Code]] - [[compile]]d instructions
{{Feature|ofp|{{ofp}} takes [[String]].}}
 
|r2= [[Anything]] - the last value given in the function is returned. See the topic [[Function#Return_Values|Function]] for more information.
 
|s3= hashMapObj [[call]] [methodName, arguments]
 
|s3since= arma3 2.14
 
|p41= hashMapObj: [[HashMap]] - the HashMap (not necessarily created through [[createHashMapObject]]) to call the method on
 
|p42= methodName: [[String]] - the name of the method to call (the method must be defined in ''hashMapObj''; see [[createHashMapObject]])
 
|p43= arguments: [[Anything]] - (Optional, default [[nil]]) arguments that are passed to the method in the <sqf inline>_this</sqf> variable
 
|r3= [[Anything]] - the value returned by the ''methodName'' method
 
|x1= <sqf>call { hint str 123; };</sqf>
 
|x2= <sqf>123 call { hint str _this; };</sqf>
 
|x3= <sqf>
_sum = [1, 2] call { (_this select 0) + (_this select 1); };
hint str _sum; // displays 3
</sqf>


<h3 style="display:none">Notes</h3>
|x4= <sqf>123 call compile "hint str _this;";</sqf>
<dl class="command_description">
<!-- Note Section BEGIN -->


This command syntax only works in OFP. In Arma, the call command can only be passed code data type, not string data type.
|x5= <sqf>_result = 123 call compile preprocessFileLineNumbers "myFile.sqf";</sqf>


To change a string data type to a code data type, use the [[compile]] command. Example:
|x6= <sqf>
private _hashMapObj = createHashMapObject [[
["MyMethod", { systemChat ("MyMethod has been called with the following arguments: " + str _this); }]
]];


<pre>
_hashMapObj call ["MyMethod", ["Hello there", player, 123]]; // hints 'MyMethod has been called with the following arguments: ["Hello there", player, 123]'
_function = loadfile "myfunc.sqf";
</sqf>
call compile _function;
</pre>


See the [[call_code]] article for more details.
|seealso= [[spawn]] [[execVM]] [[canSuspend]] [[compile]] [[compileScript]] [[preprocessFile]] [[remoteExec]] [[remoteExecCall]]
--[[User:General Barron|General Barron]] 09:12, 16 January 2009 (CET)
}}


<!-- Note Section END -->
{{Note
</dl>
|user= Leopard20
|timestamp= 20211105105249
|text= Contrary to a widespread misconception in the community, [[call]] doesn't necessarily execute the code in the [[Scheduler#Unscheduled_Environment|Unscheduled Environment]]. [[call|Call]] simply means: "execute the code here", just like how you execute a code using [[then]] (<sqf inline>if (true) then _code</sqf>) or [[do]]. Therefore it does not change the environment:
{{{!}} class="wikitable"
{{!}}-
! ''[[call]]'' executed in environment: !! Resulting environment of the code:
{{!}}-
{{!}} Scheduled {{!}}{{!}} Scheduled
{{!}}-
{{!}} Unscheduled {{!}}{{!}} Unscheduled
{{!}}}
This means that doing something like this (which is misused very often):
<sqf>
private _handle = _params spawn MY_fnc_Function;
waitUntil { scriptDone _handle };
</sqf>


<h3 style="display:none">Bottom Section</h3>
is not needed, because a lot of performance would be wasted compared to simply doing this:
<sqf>_params call MY_fnc_Function;</sqf>


which does the exact same thing as the previous code, except no new ''"scheduler thread"'' is created and the function executes seamlessly, plus the added performance benefit as mentioned before.<br>
If it is necessary to execute a code in the [[Scheduler#Unscheduled_Environment|Unscheduled Environment]], one can use [[isNil]] instead:
<sqf>isNil {_params call MY_fnc_Function}; // MY_fnc_Function is always executed unscheduled, regardless of the current environment</sqf>


[[Category:Scripting Commands|CALL]]
or if there are no parameters, one can simply do this:
[[Category:Scripting Commands OFP 1.96|CALL]]
<sqf>isNil MY_fnc_Function</sqf>
[[Category:Scripting Commands ArmA|CALL]]
}}
[[Category:Command Group: Program Flow|CALL]]

Latest revision as of 17:57, 24 May 2024

Hover & click on the images for description

Description

Description:
Adds given set of compiled instructions to the current stack and waits for it to finish and return, provides an option to pass arguments to the executed Code. See Scheduler to learn more about how the code is executed and behaves.
Groups:
Program Flow

Syntax 1

Syntax:
call code
Parameters:
code: Code - compiled instructions
Operation Flashpoint
Operation Flashpoint takes String.
This way of calling has access to its parent scope's _this, as all it does is creating a scope.
Return Value:
Anything - the last value given in the function is returned - see the topic Function for more information

Syntax 2

Syntax:
args call code
Parameters:
args: Anything - arguments that are passed to the function in the _this variable.
code: Code - compiled instructions
Operation Flashpoint
Operation Flashpoint takes String.
Return Value:
Anything - the last value given in the function is returned. See the topic Function for more information.

Syntax 3

Syntax:
hashMapObj call [methodName, arguments]
Parameters:
hashMapObj: HashMap - the HashMap (not necessarily created through createHashMapObject) to call the method on
methodName: String - the name of the method to call (the method must be defined in hashMapObj; see createHashMapObject)
arguments: Anything - (Optional, default nil) arguments that are passed to the method in the _this variable
Return Value:
Anything - the value returned by the methodName method

Examples

Example 1:
call { hint str 123; };
Example 2:
123 call { hint str _this; };
Example 3:
_sum = [1, 2] call { (_this select 0) + (_this select 1); }; hint str _sum; // displays 3
Example 4:
123 call compile "hint str _this;";
Example 5:
_result = 123 call compile preprocessFileLineNumbers "myFile.sqf";
Example 6:
private _hashMapObj = createHashMapObject [[ ["MyMethod", { systemChat ("MyMethod has been called with the following arguments: " + str _this); }] ]]; _hashMapObj call ["MyMethod", ["Hello there", player, 123]]; // hints 'MyMethod has been called with the following arguments: ["Hello there", player, 123]'

Additional Information

See also:
spawn execVM canSuspend compile compileScript preprocessFile remoteExec remoteExecCall

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
Leopard20 - c
Posted on Nov 05, 2021 - 10:52 (UTC)
Contrary to a widespread misconception in the community, call doesn't necessarily execute the code in the Unscheduled Environment. Call simply means: "execute the code here", just like how you execute a code using then (if (true) then _code) or do. Therefore it does not change the environment:
call executed in environment: Resulting environment of the code:
Scheduled Scheduled
Unscheduled Unscheduled

This means that doing something like this (which is misused very often):

private _handle = _params spawn MY_fnc_Function; waitUntil { scriptDone _handle };

is not needed, because a lot of performance would be wasted compared to simply doing this:

_params call MY_fnc_Function;

which does the exact same thing as the previous code, except no new "scheduler thread" is created and the function executes seamlessly, plus the added performance benefit as mentioned before.
If it is necessary to execute a code in the Unscheduled Environment, one can use isNil instead:

isNil {_params call MY_fnc_Function}; // MY_fnc_Function is always executed unscheduled, regardless of the current environment

or if there are no parameters, one can simply do this:

isNil MY_fnc_Function