Chapter 9
Global Scope Signals and Parameterless Procedures
9-4
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Limitations
This section identifies some of the limitations of scoped output.
Unsupported Blocks
The following list presents the blocks that do not support scoped outputs.
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Blocks that are not supported by AutoCode
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Write-to Variable Block
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DataStore
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Any block that can never have outputs, such as Text Block and
Sequencer
Connection to External Output
It is possible to connect a Global Scope output to a subsystem/system
external output pin. A Global Scope output cannot be used to implicitly
communicate between subsystems and/or the system output. If you connect
your model this way, there will be a copy from the global variable into the
external output structure for that system/subsystem. That copy occurs at the
end of the subsystem execution order.
Variable Block Aliasing
You cannot name a Global Scope label or name that matches the name of
the variable block or %var variable. AutoCode will mangle the name of the
Global Scope signal in that situation.
Monitored Signals within a Procedure SuperBlock
The implementation of monitoring signals uses global variables. That
means there is only one set of global variables for each use of the
procedure. By definition, that means that procedures that use monitored
signals are no longer re-entrant.
Monitoring Procedure External Outputs
The external outputs of a Procedure SuperBlock cannot be safely
monitored. The reason is that the concept of monitoring is in conflict with
the parameterless procedure feature. Therefore, external outputs of a
procedure cannot use a safe global variable and must be considered a part
of a parameterless interface to that procedure.