For Geosoft functions that do not return an error 

//                      condition (all of them except those specifically designed

//                      for DLL use) you must call this function to test if an

//                      error has occured in the Geosoft function.  If an error

//                      has occured, just clean-up and return.  Error messages

//                      will have been registered by the Geosoft function.

public int iCheckError()

Public Function iCheckError As Integer

public:
int iCheckError()

member iCheckError : unit -> int 

Return Value

Reference