gCao Object

A gCao object controls the generation and/or delete of a provider.
A gCao object is an array-type data that has 10 elements (0 to 9), and its each element corresponds to CaoWorkspace object of ORiN2.

"Cao" and "gCao"

In PacScript language, Cao object and gCao object are the same data type (CaoWorkspace).
The figure above shows the relationship of Cao and gCao in PacScript language.
Each task (program) has only one local "Cao" object, which is an embedded object.
Cao objects in different tasks are independent, so they do not affect each other.

On the other hand, a "gCao" object exists outside of the task (program) as a global object.
Therefore, if different tasks refer the same element number of gCao, these tasks will affect each other.
(For example; when both Task 1 and Task 2 refer gCao[0].)

Reference of Element

There are two formats to refer to the number "n" of a gCao object as follows.

1. gCao? format
   Enter a digit from 0 to 9 immediately after "gCao". (For example, gCao0, gCao2)
   Use this format when the referred element is static.
2. gCao[n] format
   Enter a variable or formula whose calculation result will be 0 to 9, with square brackets, immediately after "gCao".
   The formula is evaluated dynamically when it is executed.
   Use this format when the referred element is dynamic.

Creation and Delete of Objects

Unlike Cao objects, the creation and delete of gCao object is independent of PacScript tasks. gCao object always exists in the global area of PacScript language and will not disappear.

However, objects in each element of gCao object are correlated within referred tasks.

• If gCao[n] is referred by "task A", when task A stops, a provider cancel request (Provider Cancel) will be issued for all providers where gCao[n] is used.
• If gCao[n] is referred by "task A", when task A starts, a provider clear request (Provider Clear) will be issued for all providers where gCao[n] is used.

Precautions when the Same Element of gCao Object is Used by Multiple Tasks

If a task stops, a provider cancel request (ProviderCancel) will be executed for gCao[n] where the task refers.

It means the provider cancel request will be executed for ongoing process of all providers under gCao[n].Controllers that have been generated by gCao[n].AddController().

This operation will force providers to cancel the ongoing process, issue an error, leading to the tasks that refer the same gCao[n] to stop.

In order not to be affected by other tasks, use different gCao element number from other tasks.

Related Command

For command specifications, refer to Cao object.
gCao object and Cao object are the same object type.

Example

'Tsr0.pcs

Sub Main
    
    
    I0 = 0 'Clear a flag
    
    
    'Add QRCode provider to gCao0.
    Dim qr As Object
    qr = gCao[0].AddController( "QRCode", "CaoProv.DENSO.QRCode", "", "Conn=Com:2" )
    
    Do
        Delay 100
        If I0 = 1 Then Exit Do 'wait until the flag becomes 1
    Loop
    
    'Delete QRCode provider from gCao0.
    gCao[0].Controllers.Remove "QRCode"
    
End Sub

'Tsr1.pcs

Sub Main
    
    
    'Wait until QRCode is added to gCao0.
    Do
        Delay 100
        If gCao[0].Controllers.IsMember( "QRCode" ) Then Exit Do
    Loop
    
    'Obtain QRCode objects from gCao0.
    Dim qr As Object
    qr = gCao[0].Controllers.Item( "QRCode" )
    
    ': Execute qr command. 
    
    I0 = 1 'Set the flag to 1 because it is not necessary anymore.
    
End Sub