In the FAT file system, only date and time information contained in level-1 file information can be modified. Zero is returned for the creation and access dates and times.

To return information contained in any of the file information levels, DosProtectQueryFileInfo must be able to read the open file. DosProtectQueryFileInfo works only when the file is opened for read access, with a deny-write sharing mode specified for access by other processes. If another process that has specified conflicting sharing and access modes has already opened the file, any call to DosProtectOpen will fail.

DosProtectEnumAttribute returns the lengths of extended attributes. This information can be used to calculate what size pInfo needs to be to hold full-extended-attribute (FEA) information returned by DosProtectQueryFileInfo when Level 3 is specified. The size of the buffer is calculated as follows:

Four bytes (for oNextEntryOffset) +
One byte (for fEA) +
One byte (for cbName) +
Two bytes (for cbValue) +
Value of cbName (for the name of the EA) +
One byte (for terminating NULL in cbName) +
Value of cbValue (for the value of the EA)