How do I know if a file is in use?

Hi,

I've made a program that can checkout files from Visual Source Safe.

But the problem is, that a user could be using the file he's about to checkout, which could cause an error later.

So I wan't to be able to check if a file is in use. How to?

Thanks

/Bitz

[kedaman]

Try something like this

on local error resume next
ff=freefile:err=0
Open file for binary access write as ff
close ff
if err then
 'is accessed
end if
on error goto 0

Sorry, not working.

I tried opening a textfile in notepad, and the executed
the program, but that didn't gave an error.

Thanks for trying,

/Bitz

[kedaman]

Actually notepad doesn't leave the file open, it onlly opens it when you open or save files. But if you try something with word documents it would probably raise an error.

You could tell if a file is open by knowing it's exe file path.

Private Declare Function GetWindowsDirectory Lib "kernel32" Alias "GetWindowsDirectoryA" (ByVal lpBuffer As String, ByVal nSize As Long) As Long

Public Declare Function Process32First Lib "kernel32" ( _
         ByVal hSnapshot As Long, lppe As PROCESSENTRY32) As Long

Public Declare Function Process32Next Lib "kernel32" ( _
   ByVal hSnapshot As Long, lppe As PROCESSENTRY32) As Long

Public Declare Function CloseHandle Lib "Kernel32.dll" _
   (ByVal Handle As Long) As Long

Public Declare Function OpenProcess Lib "Kernel32.dll" _
  (ByVal dwDesiredAccessas As Long, ByVal bInheritHandle As Long, _
      ByVal dwProcId As Long) As Long

Public Declare Function EnumProcesses Lib "psapi.dll" _
   (ByRef lpidProcess As Long, ByVal cb As Long, _
      ByRef cbNeeded As Long) As Long

Public Declare Function GetModuleFileNameExA Lib "psapi.dll" _
   (ByVal hProcess As Long, ByVal hModule As Long, _
      ByVal strModuleName As String, ByVal nSize As Long) As Long

Public Declare Function EnumProcessModules Lib "psapi.dll" _
   (ByVal hProcess As Long, ByRef lphModule As Long, _
      ByVal cb As Long, ByRef cbNeeded As Long) As Long

Public Declare Function CreateToolhelp32Snapshot Lib "kernel32" ( _
   ByVal dwFlags As Long, ByVal th32ProcessID As Long) As Long

Public Declare Function GetVersionExA Lib "kernel32" _
   (lpVersionInformation As OSVERSIONINFO) As Integer

Public Type PROCESSENTRY32
   dwSize As Long
   cntUsage As Long
   th32ProcessID As Long           ' This process
   th32DefaultHeapID As Long
   th32ModuleID As Long            ' Associated exe
   cntThreads As Long
   th32ParentProcessID As Long     ' This process's parent process
   pcPriClassBase As Long          ' Base priority of process threads
   dwFlags As Long
   szExeFile As String * 260       ' MAX_PATH
End Type

Public Type OSVERSIONINFO
   dwOSVersionInfoSize As Long
   dwMajorVersion As Long
   dwMinorVersion As Long
   dwBuildNumber As Long
   dwPlatformId As Long           '1 = Windows 95.
                                  '2 = Windows NT

   szCSDVersion As String * 128
End Type

Public Const PROCESS_QUERY_INFORMATION = 1024
Public Const PROCESS_VM_READ = 16
Public Const MAX_PATH = 260
Public Const STANDARD_RIGHTS_REQUIRED = &HF0000
Public Const SYNCHRONIZE = &H100000
'STANDARD_RIGHTS_REQUIRED Or SYNCHRONIZE Or &HFFF
Public Const PROCESS_ALL_ACCESS = &H1F0FFF
Public Const TH32CS_SNAPPROCESS = &H2&
Public Const hNull = 0

Public Enum ePlatform
    eWin95_98 = 1
    eWinNT = 2
End Enum

Public gDBType As String

Public Function IsApplicationRunning(pEXEName As String) As Boolean

    On Error Resume Next
    
    Select Case getVersion()
        Case eWin95_98
            Dim lProc As Long, strName As String
            Dim hSnap As Long, proc As PROCESSENTRY32
            
            hSnap = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0)
            If hSnap = hNull Then Exit Function
            proc.dwSize = Len(proc)
            ' Iterate through the processes
            lProc = Process32First(hSnap, proc)
            Do While lProc
                strName = StrZToStr(proc.szExeFile)
                If InStr(UCase(strName), UCase(pEXEName)) Then
                    IsApplicationRunning = True
                    Exit Function
                End If
                lProc = Process32Next(hSnap, proc)
            Loop
    Case eWinNT
        Dim cb As Long
        Dim cbNeeded As Long
        Dim NumElements As Long
        Dim lProcessIDs() As Long
        Dim cbNeeded2 As Long
        Dim lNumElements2 As Long
        Dim lModules(1 To 200) As Long
        Dim lRet As Long
        Dim strModuleName As String
        Dim nSize As Long
        Dim hProcess As Long
        Dim i As Long
        
        'Get the array containing the process id's for each process object
        cb = 8
        cbNeeded = 96
        Do While cb <= cbNeeded
            cb = cb * 2
            ReDim lProcessIDs(cb / 4) As Long
            lRet = EnumProcesses(lProcessIDs(1), cb, cbNeeded)
        Loop
        NumElements = cbNeeded / 4
        For i = 1 To NumElements
            'Get a handle to the Process
            hProcess = OpenProcess(PROCESS_QUERY_INFORMATION _
            Or PROCESS_VM_READ, 0, lProcessIDs(i))
            'Got a Process handle
            If hProcess <> 0 Then
                'Get an array of the module handles for the specified
                'process
                lRet = EnumProcessModules(hProcess, lModules(1), 200, _
                        cbNeeded2)
                'If the Module Array is retrieved, Get the ModuleFileName
                If lRet <> 0 Then
                    strModuleName = Space(MAX_PATH)
                    nSize = 500
                    lRet = GetModuleFileNameExA(hProcess, lModules(1), _
                    strModuleName, nSize)
                    strModuleName = Left(strModuleName, lRet)
                    'Check for the client application running
                    If InStr(UCase(strModuleName), UCase(pEXEName)) Then
                        IsApplicationRunning = True
                        Exit Function
                    End If
                    'List1.AddItem Left(strModuleName, lRet)
                End If
            End If
            'Close the handle to the process
            lRet = CloseHandle(hProcess)
        Next
    End Select
End Function

Function StrZToStr(pString As String) As String
   StrZToStr = Left$(pString, Len(pString) - 1)
End Function

Public Function getVersion() As ePlatform
   Dim osinfo As OSVERSIONINFO
   Dim lRetVal As Integer
   
   osinfo.dwOSVersionInfoSize = 148
   osinfo.szCSDVersion = Space$(128)
   lRetVal = GetVersionExA(osinfo)
   getVersion = osinfo.dwPlatformId
End Function

Usage:

If IsApplicationRunning("C:\program.exe") Then
    MsgBox "Application is running."
Else
    MsgBox "Application is not running."
End If