Sets the current working volume (CWV) number (the default volume)
#include <nwfileng.h>
LONG FESetCWVnum (
LONG CWVnum);
(IN) Specifies the number of the volume that is to become the default volume for the current thread group.
This function returns the old CWV number.
The FESetCWVnum function sets the volume number that is to be used as the default for parsing pathnames that are not full volume paths.