dtecting if a file is presently open

Greetings,

OK, here;'s the pseudocode. Are there command or properties to make it a reality?

' open a given file
' if the file is already opened by another user then
'MsgBox "Another user is presently using this file.
Data corruption may occur."
'end if

For example is there some file property I can evaluate to determine if the file is presently open?

Thank you,
Jim

just open the file. If you get an error #55, then it is already open and you will not be allowed to open it so "data corruption" is not an issue as you can't write to a file that someone else has open.

Quote:

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Originally posted by phinds
just open the file. If you get an error #55, then it is already open and you will not be allowed to open it so "data corruption" is not an issue as you can't write to a file that someone else has open.

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What if they are using Terminal Services?

Delete the file :D , and if you can delete it, then it's not open

Actually, a safer way, would be to rename the file... and if you can rename it, then it's not open

VB Code:

'Determine whether a file is already open or not
Private Declare Function lOpen Lib "kernel32" Alias "_lopen" (ByVal lpPathName As String, ByVal iReadWrite As Long) As Long
Private Declare Function lClose Lib "kernel32" Alias "_lclose" (ByVal hFile As Long) As Long
Private Function IsFileAlreadyOpen(FileName As String) As Boolean
    Dim hFile As Long
    Dim lastErr As Long
    ' Initialize file handle and error variable.
    hFile = -1
    lastErr = 0
    ' Open for for read and exclusive sharing.
    hFile = lOpen(FileName, &H10)
    ' If we couldn't open the file, get the last error.
    If hFile = -1 Then
        lastErr = Err.LastDllError
    Else
        ' Make sure we close the file on success.
        lClose (hFile)
    End If
    ' Check for sharing violation error.
    sFileAlreadyOpen = (hFile = -1) And (lastErr = 32)
End Function
Private Sub Form_Load()
    'example by Matthew Gates ([email protected])
    MsgBox IsFileAlreadyOpen("c:\autoexec.bat")
End Sub

I might be wrong, but if you open the file with this flag: FILE_SHARE_READ_WRITE, then it means that the file can be opened in the same time with another program ? So if that flag is used then the second Open will not return an error.

JimMuglia


If you open the file exclusive no sharing, you will either open the file or get an error if it is already open.