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  >  Docs Center  >  ENVI API  >  Processing  >  ENVIAbortableTaskFromProcedure::PreExecute

ENVIAbortableTaskFromProcedure::PreExecute

ENVIAbortableTaskFromProcedure::PreExecute

The PreExecute method is called first when ENVITask::Execute runs. It performs the following actions:

  • Resets all output parameters to !NULL.
  • Updates input parameter values from keywords set on ENVITask::Execute.
  • Generates temporary files and folders for input ENVIURI and ENVIVirtualizableURI parameters, if not set by the end user.
  • Verifies that input URI parameters that generate output have write permissions and do not already exist.
  • Validates that all required input parameters are set.

Syntax


In most cases, the PreExecute method is called by ENVITask::Execute. The only time it should be called explicitly is when a base class other than ENVIAbortableTaskFromProcedure overrides ENVITask::Execute. When called explicitly, the syntax is as follows:

Obj -> [ENVIAbortableTaskFromProcedure::]PreExecute, _REF_EXTRA=refExtra

Routine Signature


To overload an object class in order to add more functionality to PreExecute, implement a method with the following signature:

PRO class::PreExecute, _REF_EXTRA=refExtra

Version History


ENVI 5.3

Introduced

API Version


3.2

See Also


ENVITask, ENVIAbortableTaskFromProcedure, Custom Tasks



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