set_canonical — sets the type of a point.
(set_canonical pointname canonical_type [force])
pointname
The full name of the point, with domain.
canonical_type
Either a number with a legal numeric VT_TYPE
value, or one of: I1, I2,
I4, UI1,
UI2, UI4,
CY, DATE,
BOOL, BSTR,
R4, R8,
EMPTY, I1 ARRAY,
I2 ARRAY, I4 ARRAY,
UI1 ARRAY, UI2 ARRAY,
UI4 ARRAY, CY ARRAY,
DATE ARRAY, BOOL ARRAY,
BSTR ARRAY, R4 ARRAY,
R8 ARRAY.
force
A value of 1 forces a change in canonical type.
A value of 0, or the omission of this optional
parameter, will allow the canonical type to change only if it is
currently EMPTY.
A message indicating success or error. Please refer to Return Syntax for details.
This command sets the canonical type of a point. Normally a point's canonical
type is EMPTY, meaning that it will maintain the data type of
whatever data is written to it. If the canonical type is other than
EMPTY, then any data written to the point will be
converted to that type before it is stored.
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When a point has a non-empty canonical type it is possible that the conversion could fail, in which case the point value is not changed. |