====== ExportShared ======
Global Sync Variable((Originally called "Shared Variable", but the naming has been revised to "Global Sync Variable" in order to clearly indicate that it is one of the "[[en/vci/script/reference/syncvariable|Sync Variables]]" along with "[[en/vci/script/reference/exportstate|Item Sync Variable]]".)). A feature to store variables to the room without associating them to specific items.

<file lua main.lua>
if vci.assets.IsMine then -- The user who spawned the item initializes the state
    vci.studio.shared.Set('switch', 0) 
end
     
function onUse(use)
    print('use')
    vci.studio.shared.Set('switch', 1)
end

function onUnuse(use)
    print('unuse')
    vci.studio.shared.Set('switch', 0)
end
</file>

Bind is somewhat similar to updateAll, but it is a little different.

<file lua main.lua>
-- Bind. Called only when the variable is changed
vci.studio.shared.Bind('switch', function(value)
    if value==1 then
        vci.assets.SetMaterialColorFromIndex(4, Color.__new(1, 0, 0, 1))
    else
        vci.assets.SetMaterialColorFromIndex(4, Color.__new(0.5, 0.5, 0.5, 1))
    end
end)
</file>

<file lua main.lua>
-- Bind. Called every frame even the value is not changed
function updateAll() -- This is run by all users regardless of ownership
    --print(vci.state.Get('switch'))
    if vci.studio.shared.Get('switch')==1 then
        vci.assets.SetMaterialColorFromIndex(4, Color.__new(1, 0, 0, 1))
    else
        vci.assets.SetMaterialColorFromIndex(4, Color.__new(0.5, 0.5, 0.5, 1))
    end
end
</file>

===== Set() =====
==== Arguments ====
  * name : string
  * value : number, string

===== Get() =====
==== Arguments ====
  * name : string
==== Return values ====
  * number, string

===== Bind() =====
==== Arguments ====
  * name : string
  * callback : function

==== Summary ====
It was implemented in the past when updateAll was still not available.

===== Add() =====
==== Arguments ====
  * name : string
  * value : usertype

==== Summary ====
Please refer to ExportState.Add.

===== The weakness of the global sync variable and alternate solution =====
The global sync variable has some weaknesses in its implementation.

  * There is no way to avoid the overlap of variable names in between items
  * We cannot clear the variables as we cannot know the owner of the variable

==== Example of using "vci.state + message" in place of "vci.studio.shared.Get" ====

=== In case of global sync variable ===

<file lua main.lua>
local value = vci.studio.shared.Get('valueName')
</file>

=== The alternative ===

== The one to Get ==

<file lua main.lua>
-- Define the function to receive the value beforehand
message.On('response_valueName', function()

end)
-- Request the Value
message.Emit('request_valueName')
</file>

== The one to be inquired ==

<file lua main.lua>
-- When the value is requested
message.On('request_valueName', function() 
    -- Acquire a value from the item sync variable and return
    vci.Emit('respone_valueName', vci.state.Get('valueName'))
end)
</file>

It is a little clumsy