Is file in use?

[OlgaV]

Hi!

Can anyone please tell me how to perform a simple check on a file - if it is in use or not. I can't afford to be opening files from my program to get error msgs and therefore assume that files are being used. Is there an API that does it?

Thank you!!!!

[Jop]

I can't afford to be opening files from my program to get
error msgs and therefore assume that files are being used.

Why not? I think the error message "File already open" can only mean one thing (maybe I'm wrong) namely that's in use with another app.
I think it's a pretty save way to assume the file is in use by trapping this error.

But if you really need the api way you'll probably find something at allapi.net, vbaccelerator.com or VBnet (http://www.mvps.org/vbnet/)
I couldn't find something it my api-viewer though

Try this:

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


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.
 If (hFile = -1) And (lastErr = 32) Then
    IsFileAlreadyOpen = True
    Else
    IsFileAlreadyOpen = False
 End If
End Function


'Usage:

Private Sub Command1_Click()
If IsFileAlreadyOpen("C:\program.exe") Then
MsgBox "File open!"
Else
MsgBox "File not open!"
End If
End Sub

[OlgaV]

Matthew,

Unfortunately your code didn't work. I had a file opened while my program ran, and the program did not detect it...
I'm running WinNT (if it matters).

Would you have any other suggestions?

Many thanks.