Contents
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National Instruments Corporation
ix
System External Interface Layer .....................................................................5-7
Discrete Subsystem Interface Layer ................................................................5-8
iinfo ...................................................................................................5-9
R_P and I_P ......................................................................................5-9
State Data ..........................................................................................5-9
Procedure Data ..................................................................................5-10
Pre-init Phase...................................................................................................5-10
Init, Output, and State Phases..........................................................................5-10
Copy Back and Duplicates ..............................................................................5-10
Error Handling.................................................................................................5-11
Structure-Based Interface ................................................................................5-11
Unrolled Interface............................................................................................5-12
Phases and Error Handling ..............................................................................5-12
Referenced Percent Variables..........................................................................5-12
Procedure Arguments ......................................................................................5-15
Extended Procedure Information Structure .....................................................5-18
Caller Identification ..........................................................................5-18
Compatibility Issues..........................................................................5-19
Changing %var Values During Startup.............................................5-22
Inputs and Outputs...........................................................................................5-23
Environment Variables ....................................................................................5-24
Local Variables................................................................................................5-24
Init, Output, and State Phases..........................................................................5-25