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|descr= Repeats [[Code]] while the given condition is [[true]]. A part of [[while]]-[[do]] construct. | |descr= Repeats [[Code]] while the given condition is [[true]]. A part of [[while]]-[[do]] construct. | ||
{{Feature | Important | A while loop | {{Feature | Important | A [[while]] loop does not have any suspension, meaning that if used in [[Scheduler#Scheduled_Environment|scheduled environment]] without any suspension ([[sleep]] or [[uiSleep]]) the code will run multiple times per frame and consumes the 3 ms per frame scheduler execution limit. This should be avoided if not intended (see {{HashLink|#Example 3}}).}} | ||
|s1= [[while]] condition | |s1= [[while]] condition | ||
Line 32: | Line 32: | ||
|r1= [[While Type]] | |r1= [[While Type]] | ||
|x1= < | |x1= <sqf>while { a < b } do { a = a + 1 };</sqf> | ||
|x2= A practical example: Repair all members of a group to such a level that they are able to stand up: | |x2= A practical example: Repair all members of a group to such a level that they are able to stand up: | ||
< | <sqf> | ||
{ | |||
if (alive _x) then | |||
{ | { | ||
while { not canStand _x } do | |||
{ | { | ||
_x setDamage (damage _x - 0.01); | |||
}; | }; | ||
}; | }; | ||
} | } forEach units group unitname; | ||
|x3=<sqf>[] spawn { | </sqf> | ||
//warning | |||
|x3= <sqf> | |||
[] spawn { | |||
// warning: while loop without suspension executes multiple times per frame | |||
private _counter = 0; | private _counter = 0; | ||
private _endTime = diag_tickTime + 5; | private _endTime = diag_tickTime + 5; | ||
private _frameNo = diag_frameNo; | private _frameNo = diag_frameNo; | ||
while {diag_tickTime < _endTime} do { | while { diag_tickTime < _endTime } do | ||
{ | |||
_counter = _counter + 1; | _counter = _counter + 1; | ||
}; | }; | ||
// in an empty mission, the _counter may go well over 2000 times per frame! | |||
hint format ["Average Execution: %1 times per frame", _counter / (diag_frameNo - _frameNo)]; | hint format ["Average Execution: %1 times per frame", _counter / (diag_frameNo - _frameNo)]; | ||
//with suspension | |||
// with suspension | |||
private _counter = 0; | private _counter = 0; | ||
private _endTime = diag_tickTime + 5; | private _endTime = diag_tickTime + 5; | ||
private _frameNo = diag_frameNo; | private _frameNo = diag_frameNo; | ||
while {diag_tickTime < _endTime} do { | while { diag_tickTime < _endTime } do | ||
{ | |||
_counter = _counter + 1; | _counter = _counter + 1; | ||
uiSleep 0.001; //waits at least 1 frame | uiSleep 0.001; // waits at least 1 frame | ||
}; | }; | ||
// _counter prints one per frame, as expected | |||
hint format ["Average Execution: %1 times per frame", _counter / (diag_frameNo - _frameNo)]; | hint format ["Average Execution: %1 times per frame", _counter / (diag_frameNo - _frameNo)]; | ||
} | }; | ||
</sqf> | </sqf> | ||
|seealso= [[Control Structures]] [[waitUntil]] [[for]] [[do]] | |seealso= [[Control Structures]] [[waitUntil]] [[for]] [[do]] | ||
}} | }} |
Revision as of 18:45, 24 March 2022
Description
- Description:
- Repeats Code while the given condition is true. A part of while-do construct.
- Groups:
- Program Flow
Syntax
- Syntax:
- while condition
- Parameters:
- condition: Code
- Return Value:
- While Type
Examples
- Example 1:
- Example 2:
- A practical example: Repair all members of a group to such a level that they are able to stand up:
- Example 3:
- [] spawn { // warning: while loop without suspension executes multiple times per frame private _counter = 0; private _endTime = diag_tickTime + 5; private _frameNo = diag_frameNo; while { diag_tickTime < _endTime } do { _counter = _counter + 1; }; // in an empty mission, the _counter may go well over 2000 times per frame! hint format ["Average Execution: %1 times per frame", _counter / (diag_frameNo - _frameNo)]; // with suspension private _counter = 0; private _endTime = diag_tickTime + 5; private _frameNo = diag_frameNo; while { diag_tickTime < _endTime } do { _counter = _counter + 1; uiSleep 0.001; // waits at least 1 frame }; // _counter prints one per frame, as expected hint format ["Average Execution: %1 times per frame", _counter / (diag_frameNo - _frameNo)]; };
Additional Information
- See also:
- Control Structures waitUntil for do
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 May 14, 2008 - 08:40 (UTC)
-
The boolean code that is used to evaluate the while condition can be preceded by code that executes a regular command.
while {_a =_a + 1; _a < 10} do {...}
- Posted on Aug 30, 2014 - 08:12 (UTC)
- In non-scheduled environment, while do loop is limited to 10,000 iterations, after which it exits even if condition is still true. In scheduled environment no such limit exists.
Categories:
- Scripting Commands
- Introduced with Operation Flashpoint version 1.85
- Operation Flashpoint: New Scripting Commands
- Operation Flashpoint: Scripting Commands
- Operation Flashpoint: Elite: Scripting Commands
- ArmA: Armed Assault: Scripting Commands
- Arma 2: Scripting Commands
- Arma 2: Operation Arrowhead: Scripting Commands
- Take On Helicopters: Scripting Commands
- Arma 3: Scripting Commands
- Command Group: Program Flow