FIX: PUTFILE Command to Drive "A" Without a Floppy Causes Fault (170609)

RESOLUTION

Do not specify a drive letter in the PUTFILE command and allow the drive to be selected from the SAVE AS dialog box.

NOTE: This is not the best remedy for this problem but it does prevent the Invalid Page Fault and subsequent closing of Visual FoxPro. The Invalid Page Fault does not occur in Visual FoxPro 3.0b.

A better alternative to receiving the Invalid Page Fault is to verify whether the floppy drive has a disk in it prior to issuing the PUTFILE command. The following code is a function to which you pass to drive letter that is checked. The function returns a True (.T.) if there is a disk in the drive and a False (.F.) if the drive is empty.

   **********************************************************
   * FUNCTION isdiskin
   **********************************************************
   *
   * Passed  - drive root specification, such as "A:\", "B:\", etc
   * Returns - logical .T., .F. depending on whether drive exists
   *
   * Usage -
   * ? isdiskin("A:\")
   *
   * Any drive formatted with an MS operating system > DOS 3.3 will
   * have a nonzero volume serial number. If the specified drive
   * doesn't exist, it will return a 0 volume serial number. So,
   * GetVolumeInformation() can function as a  replacement
   * for the old IsDiskIn.Bin that used to ship with FoxPro for DOS.
    PARAMETERS m.rootpath

   DECLARE GetVolumeInformation IN win32api STRING, STRING @, ;
       INTEGER, INTEGER @, INTEGER @, INTEGER @, STRING @, INTEGER

   m.volname = SPACE(255)
   m.volnamelen = LEN(m.volname)
   m.volumeserialnumber = 0
   m.maxfilenamelen = 0
   m.filesystemflags = 0
   m.filesystemname = SPACE(255)
   m.fsnamelen = LEN(m.filesystemname)

   =GetVolumeInformation(m.rootpath, @m.volname, m.volnamelen, ;
       @m.volumeserialnumber, @m.maxfilenamelen, ;
       @m.filesystemflags, @m.filesystemname, m.fsnamelen)
    IF m.volumeserialnumber = 0
      RETURN .F.
   ELSE
      RETURN .T.
   ENDIF
				

Another resolution to the Invalid Page Fault problem is to issue a DISKSPACE("A"). This command returns a -1 if there is no disk in Drive "A" and returns some number greater than -1 if there is a disk in Drive "A."

   ? PUTFILE("Label File","A:\test","dbf")