To use DosSetPathInfo to set any level of file information for a file or subdirectory, a process must have exclusive write access to the closed file object. Thus, if the file object is already accessed by another process, any call to DosSetPathInfo will fail.

A value of 0 in the date and time components of a field causes that field to be left unchanged. For example, if both "last write date" and "last write time" are specified as 0 in the Level 1 information structure, then both attributes of the file are left unchanged. If either "last write date" or "last write time" are other than 0, then both attributes of the file are set to the new values.

For data integrity purposes, the Write-Through bit in flOptions should be used only to write the extended attributes to the disk immediately, instead of caching them and writing them later. Having the Write-Through bit set constantly can degrade performance.

In the FAT file system, only the dates and times of the last write can be modified. Creation and last-access dates and times are not affected.

The last-modification date and time will be changed if the extended attributes are modified.