isNull: Difference between revisions

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m (Some wiki formatting)
m (Some wiki formatting)
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{{!}} [[Location]]
{{!}} [[Location]]
{{!}} [[Task]]
{{!}} [[Task]]
{{!}} [[Script]]
{{!}} [[Script Handle|Script]]
{{!}} [[Config]]
{{!}} [[Config]]
{{!}} [[Diary Record]]
{{!}} [[Diary Record]]
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{{!}}}
{{!}}}


{{Feature | important | A test via {{=}}{{=}} does '''not''' work, because a null value is not equal to anything, not even itself ([[configNull]] being the exception).
{{Feature|important|2= A test via [[a == b|==]] does '''not''' work because a null value is not equal to anything, not even itself ([[configNull]] being the exception).
See also [[isEqualTo]].}}
See also [[isEqualTo]].}}


|s1= [[isNull]] entity
|s1= [[isNull]] entity


|p1= entity: [[Object]], [[Control]], [[Display]], [[Group]], [[Location]], [[Task]], [[Script]], [[Config]] or [[Diary Record]]
|p1= entity: [[Object]], [[Control]], [[Display]], [[Group]], [[Location]], [[Task]], [[Script Handle]], [[Config]] or [[Diary Record]]


|r1= [[Boolean]]
|r1= [[Boolean]]
Line 84: Line 84:


|x2= [[Diary Record]] support before {{GVI|arma3|2.00}}:
|x2= [[Diary Record]] support before {{GVI|arma3|2.00}}:
<sqf>private _nullRecord = objNull createDiaryRecord []; // wrong parameters = failure to create a record = null value
<sqf>
private _nullRecord = objNull createDiaryRecord []; // wrong parameters = failure to create a record = null value
private _createdRecord = player createDiaryRecord ["Diary", ["title", "description"]];
private _createdRecord = player createDiaryRecord ["Diary", ["title", "description"]];
if (_createdRecord isEqualTo _nullRecord) then { hint "Failed" };</sqf>
if (_createdRecord isEqualTo _nullRecord) then { hint "Failed" };
</sqf>


[[Team Member]] support before {{GVI|arma3|2.10}}:
[[Team Member]] support before {{GVI|arma3|2.10}}:

Revision as of 10:04, 29 December 2022

Hover & click on the images for description

Description

Description:
Checks whether the tested item is null.
Which null type the item has to be equal to depends on the type of game entity tested:
Type Object Group Control Display Location Task Script Config Diary Record Team Member
Null value objNull grpNull controlNull displayNull locationNull taskNull scriptNull configNull diaryRecordNull teamMemberNull
Since Logo A0.png1.00 Logo A0.png1.00 Logo A1 black.png1.00 Logo A1 black.png1.00 Logo A2.png1.00 Logo A2.png1.00 Arma 3 logo black.png1.30 Arma 3 logo black.png1.54 Arma 3 logo black.png2.00 Arma 3 logo black.png2.10
A test via == does not work because a null value is not equal to anything, not even itself (configNull being the exception). See also isEqualTo.
Groups:
Variables

Syntax

Syntax:
isNull entity
Parameters:
entity: Object, Control, Display, Group, Location, Task, Script Handle, Config or Diary Record
Return Value:
Boolean

Examples

Example 1:
if (isNull obj) then { hint "obj variable is defined but obj is null"; };
Example 2:
Diary Record support before Arma 3 logo black.png2.00:
private _nullRecord = objNull createDiaryRecord []; // wrong parameters = failure to create a record = null value private _createdRecord = player createDiaryRecord ["Diary", ["title", "description"]]; if (_createdRecord isEqualTo _nullRecord) then { hint "Failed" };
Team Member support before Arma 3 logo black.png2.10:
private _isNull = _teamMember isEqualTo teamMemberNull;

Additional Information

See also:
controlNull displayNull grpNull locationNull objNull taskNull teamMemberNull scriptNull configNull typeName

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