Article ID: 170609
Article Last Modified on 3/24/2000
APPLIES TO
- Microsoft Visual FoxPro 5.0 Standard Edition
- Microsoft Visual FoxPro 5.0a
This article was previously published under Q170609
SYMPTOMS
Issuing a PUTFILE command to Drive "A" without having a floppy disk in that drive causes an Invalid Page Fault in Visual FoxPro 5.0 and 5.0a.
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."
STATUS
Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article. This has been corrected in Visual FoxPro 6.0.
MORE INFORMATION
In Visual FoxPro 5.x, if the following code is issued and there is no floppy disk in the "A" drive, an Invalid Page Fault occurs and Visual FoxPro closes:
? PUTFILE("Label File","A:\test","dbf")
The following error message appears in Windows 95:
Clicking Details reveals the following message:
In Windows NT 4.0, the following error appears:
The operating system then closes Visual FoxPro.
If the PUTFILE function is issued without specifying a drive letter, the Invalid Page Fault does not occur. A "SAVE AS" dialog box appears and if the "A" drive is selected and does not contain a floppy disk, the following non-fatal error message is issued:
REFERENCES
Visual FoxPro Help
Keywords: kberrmsg kbbug kbfix kbprb KB170609