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DataFolderRefStatus

DataFolderRefStatus (dfr)​

The DataFolderRefStatus function returns the status of a data folder reference.

Details​

DataFolderRefStatus returns zero if the data folder reference is invalid or non-zero if it is valid.

DataFolderRefStatus returns a bitwise result with bit 0 indicating if the reference is valid and bit 1 indicating if the reference data folder is free. Therefore the returned values are:

0:The data folder reference is invalid.
1:The data folder reference refers to a regular global data folder.
3:The data folder reference refers to a free data folder.

A data folder reference is invalid if it was never assigned a value or if it is assigned an invalid value. For example:

DFREF dfr                               // dfr is invalid
DFREF dfr = root:                       // dfr is valid
DFREF dfr = root:NonExistentDataFolder  // dfr is invalid
DFREF dfr = root:ExistingDataFolder     // dfr is valid
KillDataFolder dfr                      // dfr is invalid

You should use DataFolderRefStatus to test any DFREF variables that might not be valid, such as after assigning a reference when you are not sure that the referenced data folder exists. For historical reasons, if you use an invalid DFREF it will often act like root.

See Also​

Data Folders, Data Folder References, Built-in DFREF Functions