Difference between revisions of "spawn"

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m (Text replacement - "\|seealso= *\[\[([^ ]+)\]\], \[\[([^ ]+)\]\]" to "|seealso= $1 $2")
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|gr1= Program Flow
 
|gr1= Program Flow
  
|descr= Adds given set of compiled instructions to the [[Scheduler|scheduler]]. Exactly when the code will be executed is unknown, it depends on how busy is the engine and how filled up is the [[Scheduler|scheduler]]. Therefore [[spawn]] does not wait for the supplied code to finish, instead, [[spawn]] returns a [[Script Handle|Script]] handle to the [[Scheduler|scheduler]] task. [[scriptDone]] command can be used to check the code completion. Additional arguments are passed to the code in local variable [[Magic Variables#this|_this]]. Since Arma 3 v1.55 the script handle also exists inside the code in {{hl|_thisScript}} variable. To see what spawned scripts are currently in the scheduler, use [[diag_activeSQFScripts]] command.{{Feature|Warning| When multiple [[Code]] is [[spawn]]ed in an order, there is <u>no guarantee</u> that the [[spawn]]ed [[Code]] will also execute in the same order. If you need such guarantee, use [[BIS_fnc_spawnOrdered]] function}}
+
|descr= Adds given set of compiled instructions to the [[Scheduler|scheduler]].
 +
Exactly when the code will be executed is unknown, it depends on how busy is the engine and how filled up is the [[Scheduler|scheduler]].
 +
Therefore [[spawn]] does not wait for the supplied code to finish, instead, [[spawn]] returns a [[Script Handle|Script]] handle to the [[Scheduler|scheduler]] task.
 +
[[scriptDone]] command can be used to check the code completion. Additional arguments are passed to the code in local variable [[Magic Variables#this|_this]].
 +
Since {{GVI|arma3|1.56|size=0.75}} the script handle also exists inside the code in {{hl|_thisScript}} variable.
 +
To see what spawned scripts are currently in the scheduler, use [[diag_activeSQFScripts]] command.
 +
 
 +
{{Feature|warning| When multiple [[Code]] is [[spawn]]ed in an order, there is <u>no guarantee</u> that the [[spawn]]ed [[Code]] will execute in the same order (see {{HashLink|Example 2}}). If the order is important, use [[BIS_fnc_spawnOrdered]].}}
  
 
|s1= arguments [[spawn]] code
 
|s1= arguments [[spawn]] code
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|p2= code: [[Code]]
 
|p2= code: [[Code]]
  
|r1= [[Script Handle]] - can be used to determine (via [[scriptDone]] (also via [[isNull]] in Arma 3)) when the spawned script has finished. In Arma 3, the handle is also available inside the spawned script in {{hl|_thisScript}} variable.
+
|r1= [[Script Handle]] - can be used to determine (''via'' [[scriptDone]] (also ''via'' [[isNull]] in {{arma3}})) when the spawned script has finished. In {{arma3}}, the handle is also available inside the spawned script in {{hl|_thisScript}} variable
  
|x1= <code>_handle = [] [[spawn]] {[[player]] [[globalChat]] "Hello world!"};</code>
+
|x1= <sqf>_handle = 0 spawn { player globalChat "Hello world!" };</sqf>
  
 
|x2= There is no guarantee that spawned scripts will be executed in the same order they spawned:  
 
|x2= There is no guarantee that spawned scripts will be executed in the same order they spawned:  
<code>[[for]] "_i" [[from]] 0 [[to]] 100 [[do]]
+
<sqf>
 +
for "_i" from 0 to 100 do
 
{
 
{
_null = _i [[spawn]]
+
_i spawn
 
{
 
{
[[diag_log]] _this;
+
diag_log _this;
 
};
 
};
}; {{cc|Result: 51,1,2...49,50,0,52,53...100}}</code>
+
}; // Result: 51,1,2...49,50,0,52,53...100
 +
</sqf>
  
 
|x3= Local variables declared in the main scope are not available in the spawned code. You have to pass them as parameters:
 
|x3= Local variables declared in the main scope are not available in the spawned code. You have to pass them as parameters:
<code>[[private]] _localVariable = 1234;
+
<sqf>
[_localVariable] [[spawn]]
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private _localVariable = 1234;
 +
[_localVariable] spawn  
 
{
 
{
[[systemChat]] [[format]] ["_localVariable does not exist: %1", [[isNil]] "_localVariable"]; {{cc|_localVariable does not exist: true}}
+
systemChat format ["_localVariable does not exist: %1", isNil "_localVariable"]; // _localVariable does not exist: true
[[params]] ["_localVariable"];
+
params ["_localVariable"];
[[systemChat]] [[format]] ["My _localVariable is now: %1", _localVariable]; {{cc|My _localVariable is now: 1234}}
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systemChat format ["_localVariable is now: %1", _localVariable]; // _localVariable is now: 1234
};</code>
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};
 +
</sqf>
  
 
|seealso= [[call]] [[execVM]] [[execFSM]] [[exec]] [[compile]] [[preprocessFileLineNumbers]] [[preprocessFile]] [[terminate]] [[scriptDone]] [[remoteExec]] [[sleep]] [[uiSleep]] [[canSuspend]]
 
|seealso= [[call]] [[execVM]] [[execFSM]] [[exec]] [[compile]] [[preprocessFileLineNumbers]] [[preprocessFile]] [[terminate]] [[scriptDone]] [[remoteExec]] [[sleep]] [[uiSleep]] [[canSuspend]]
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|text= [[spawn]] cannot call other local functions on the same scope as itself.<br>
 
|text= [[spawn]] cannot call other local functions on the same scope as itself.<br>
 
It can, however, call other global functions:
 
It can, however, call other global functions:
<code>_addOne = { TST = TST + 1 };
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<sqf>
 +
_addOne = { TST = TST + 1 };
 
TST_addOne = { TST = TST + 1 };
 
TST_addOne = { TST = TST + 1 };
  
 
_add = {
 
_add = {
 
TST = TST+1;
 
TST = TST+1;
[[player]] [[sideChat]] [[format]] ["added: %1",TST];
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player sideChat format ["added: %1",TST];
[] [[call]] _addOne;
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call _addOne;
[[player]] [[sideChat]] [[format]] ["called local: %1",TST];
+
player sideChat format ["called local: %1",TST];
[] [[call]] TST_addOne;
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call TST_addOne;
[[player]] [[sideChat]] [[format]] ["called global: %1",TST];
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player sideChat format ["called global: %1",TST];
 
};
 
};
 
TST = 0;
 
TST = 0;
[] [[call]] _add;
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call _add;
[] [[spawn]] _add;</code>
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0 spawn _add;
 +
</sqf>
 
The call of _addOne from the spawned function does not do anything.
 
The call of _addOne from the spawned function does not do anything.
 
}}
 
}}
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|timestamp= 20150825133900
 
|timestamp= 20150825133900
 
|text= If you want to call a local function which has NOT been created inside a spawned function, then do this:
 
|text= If you want to call a local function which has NOT been created inside a spawned function, then do this:
<code>_fncOne = { [[systemChat]] "This is _fncOne" };
+
<sqf>
_fncTwo = { [[call]] (_this [[select]] 0) };
+
_fncOne = { systemChat "This is _fncOne" };
[_fncOne] [[spawn]] _fncTwo;</code>
+
_fncTwo = { call (_this select 0) };
 +
[_fncOne] spawn _fncTwo;
 +
</sqf>
 
}}
 
}}

Latest revision as of 18:21, 5 April 2022

Hover & click on the images for description

Description

Description:
Adds given set of compiled instructions to the scheduler. Exactly when the code will be executed is unknown, it depends on how busy is the engine and how filled up is the scheduler. Therefore spawn does not wait for the supplied code to finish, instead, spawn returns a Script handle to the scheduler task. scriptDone command can be used to check the code completion. Additional arguments are passed to the code in local variable _this. Since Arma 3 logo black.png1.56 the script handle also exists inside the code in _thisScript variable. To see what spawned scripts are currently in the scheduler, use diag_activeSQFScripts command.
When multiple Code is spawned in an order, there is no guarantee that the spawned Code will execute in the same order (see Example 2 -). If the order is important, use BIS_fnc_spawnOrdered.
Groups:
Program Flow

Syntax

Syntax:
arguments spawn code
Parameters:
arguments: Anything - arguments passed to the script, which later available in _this variable inside the script.
code: Code
Return Value:
Script Handle - can be used to determine (via scriptDone (also via isNull in Arma 3)) when the spawned script has finished. In Arma 3, the handle is also available inside the spawned script in _thisScript variable

Examples

Example 1:
_handle = 0 spawn { player globalChat "Hello world!" };
Example 2:
There is no guarantee that spawned scripts will be executed in the same order they spawned:
for "_i" from 0 to 100 do { _i spawn { diag_log _this; }; }; // Result: 51,1,2...49,50,0,52,53...100
Example 3:
Local variables declared in the main scope are not available in the spawned code. You have to pass them as parameters:
private _localVariable = 1234; [_localVariable] spawn { systemChat format ["_localVariable does not exist: %1", isNil "_localVariable"]; // _localVariable does not exist: true params ["_localVariable"]; systemChat format ["_localVariable is now: %1", _localVariable]; // _localVariable is now: 1234 };

Additional Information

See also:
call execVM execFSM exec compile preprocessFileLineNumbers preprocessFile terminate scriptDone remoteExec sleep uiSleep canSuspend

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 Mar 06, 2009 - 00:20 (UTC)
Kronzky
spawn cannot call other local functions on the same scope as itself.
It can, however, call other global functions:
_addOne = { TST = TST + 1 }; TST_addOne = { TST = TST + 1 }; _add = { TST = TST+1; player sideChat format ["added: %1",TST]; call _addOne; player sideChat format ["called local: %1",TST]; call TST_addOne; player sideChat format ["called global: %1",TST]; }; TST = 0; call _add; 0 spawn _add;
The call of _addOne from the spawned function does not do anything.
Posted on Oct 21, 2014 - 23:33 (UTC)
DreadedEntity
spawn requires a script handle when used in the 2D editor. (A3)
In scripts and in the debug console, it is not required, but very useful for keeping track of running scripts. Having a script handle also makes it easy to terminate scripts at any time.

Since spawn creates a new scheduled environment, having an excess of open threads can make the scheduler queue extremely long, significantly increasing the execution time of each thread. (it takes an extremely large amount of threads, though)
Posted on Aug 25, 2015 - 13:39 (UTC)
IT07
If you want to call a local function which has NOT been created inside a spawned function, then do this:
_fncOne = { systemChat "This is _fncOne" }; _fncTwo = { call (_this select 0) }; [_fncOne] spawn _fncTwo;