Do I need to destroy a variable after use?

[Marshmalo]

Hi, I am abit confused, I have been told you need to store data in variables to stop it leaking and causing lag/crashes etc, so for example if you are selecting every unit owned by player of type, you need to store it in a variable. Thats fine, I understand that.

But do I then need to destroy that variable after I've used it to stop it leaking? And if so do I need to do this for all variables types?

 

[Maker]

http://www.hiveworkshop.com/forums/triggers-scripts-269/things-leak-35124/

 

[Marshmalo]

nice thanks that was very helpful!

 

[defskull]

If your variable is local (done in JASS Script), you must null it if it's a handle (Units, Locations, etc).

Example;

• Custom script: local unit u = GetTriggerUnit()
• Custom script: call KillUnit(u)
• Custom script: set u = null

Only null this if you're creating a local variable (Handle-type).
Variables such as Integer/Real, does not need to be nulled as they are not handles.

But I can't say for sure should we first null location, or destroy them first.
Either way, it'll work (I think).

 

[Almia]

you cannot destroy a variable.

Locals and globals you need to null must be an extended type of handle.Excluding booleans,strings,reals,and integers

 

[Marshmalo]

Ok I don't really understand all this null variable stuff, I was never pro at triggers but I will ask my triggerer friend if he can have a look at this thread and get rid of any leaks in our map, hope he will understand!

 

[Garfield1337]

If your variable is local (done in JASS Script), you must null it if it's a handle (Units, Locations, etc).

Example;

• Custom script: local unit u = GetTriggerUnit()
• Custom script: call KillUnit(u)
• Custom script: set u = null

Only null this if you're creating a local variable (Handle-type).
Variables such as Integer/Real, does not need to be nulled as they are not handles.

But I can't say for sure should we first null location, or destroy them first.
Either way, it'll work (I think).

Globals need to be nulled too, it's just that nobody does it.

You need to destroy the location before nulling it, because nulling removes the reference to the location.

Ok I don't really understand all this null variable stuff, I was never pro at triggers but I will ask my triggerer friend if he can have a look at this thread and get rid of any leaks in our map, hope he will understand!

As far as I know, variables of handle type point to the address of data instead of holding it (which would be logical, because handles are structures). Because they're being referenced by variables, a handle will not be recycled until all of the references are gone. By nulling a variable, you remove the reference and the handle is free to be recycled.

 

[shadowvzs]

Globals need to be nulled too, it's just that nobody does it.

You need to destroy the location before nulling it, because nulling removes the reference to the location.

but since u use more time the variable and location is removed by custom scripts its ok if u store different reference afyer last was solved with custom script (RemoveLocation/DestroyForce,DestroyGroup etc)

 

[Maker]

but since u use more time the variable and location is removed by custom scripts its ok if u store different reference afyer last was solved with custom script (RemoveLocation/DestroyForce,DestroyGroup etc)

You should null them, otherwise leaks occur.

 

[shadowvzs]

You should null them, otherwise leaks occur.

so this leaks if i use mroe times the variable and not null ?

set Point = Position of unit1
Call RemoveLocation(udg_Point)
set Point = Position of unit2
Call RemoveLocation(udg_Point)

 

[Maker]

so this leaks if i use mroe times the variable and not null ?

set Point = Position of unit1
Call RemoveLocation(udg_Point)
set Point = Position of unit2
Call RemoveLocation(udg_Point)

Yes, that leaks.

 

[ZiGOR]

Hi, I am abit confused, I have been told you need to store data in variables to stop it leaking and causing lag/crashes etc, so for example if you are selecting every unit owned by player of type, you need to store it in a variable. Thats fine, I understand that.

But do I then need to destroy that variable after I've used it to stop it leaking? And if so do I need to do this for all variables types?

If your data changes during the game - you should destroy unit groups/remove locations e.t.c... but if not - just leave it be ^_^

 

[defskull]

@Maker
So, we need to null, even globals ? (like what shadowvs posted)

So this is the solution ? (referring to shadowvs's post)

• Set Location = (Somewhere)
• Custom script: call RemoveLocation(udg_Location)
• Custom script: set udg_Location = null

Is it ?

 

[ZiGOR]

@Maker
So, we need to null, even globals ? (like what shadowvs posted)

So this is the solution ? (referring to shadowvs's post)

• Set Location = (Somewhere)
• Custom script: call RemoveLocation(udg_Location)
• Custom script: set udg_Location = null

Is it ?

 

[Maker]

@Maker
So, we need to null, even globals ? (like what shadowvs posted)

So this is the solution ? (referring to shadowvs's post)

• Set Location = (Somewhere)
• Custom script: call RemoveLocation(udg_Location)
• Custom script: set udg_Location = null

Is it ?

Yes.

 

[ZiGOR]

Yes.

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