spawn

From Bohemia Interactive Community
Revision as of 19:16, 28 August 2021 by Lou Montana (talk | contribs) (Text replacement - "Script Handle" to "Script Handle")
(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Jump to navigation Jump to search
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 v1.55 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 also execute in the same order. If you need such guarantee, use BIS_fnc_spawnOrdered function
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 = [] 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 { _null = _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 ["My _localVariable is now: %1", _localVariable]; // My _localVariable is now: 1234 };

Additional Information

See also:
callexecVMexecFSMexeccompilepreprocessFileLineNumberspreprocessFileterminatescriptDoneremoteExecsleepuiSleepcanSuspend

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 5 March, 2009
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; [] spawn _add; The call of _addOne from the spawned function does not do anything.
Posted on October 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 August 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;