是不是GetLogicalDrives?
The GetLogicalDrives function returns a bitmask representing the currently
available disk drives.
DWORD GetLogicalDrives(VOID)
Parameters
This function has no parameters.
Return Values
If the function succeeds, the return value is a bitmask representing
the currently available disk drives. Bit position 0 (the least-significant bit)
is drive A, bit position 1 is drive B, bit position 2 is drive C, and so on.
看看你有没有用诸如:
subst c:/test a:
之类的东西?