C# Signature:

[DllImport("kernel32.dll", SetLastError = true, CharSet = CharSet.Auto)]
static extern IntPtr OpenFileMapping(
     uint dwDesiredAccess,
     bool bInheritHandle,
     string lpName);

User-Defined Types:

None.

[DllImport("kernel32.dll", BestFitMapping = false, ThrowOnUnmappableChar = true)]
static extern int OpenFile([System.Runtime.InteropServices.MarshalAs(System.Runtime.InteropServices.UnmanagedType.LPStr)]string lpFileName, out OFSTRUCT lpReOpenBuff,
   [Enum.OpenFile] uStyle);

Notes:

None.

User-Defined Types:

[System.Runtime.InteropServices.StructLayout(LayoutKind.Sequential)]
public struct OFSTRUCT
{
  public byte cBytes;
  public byte fFixedDisc;
  public UInt16 nErrCode;
  public UInt16 Reserved1;
  public UInt16 Reserved2;
  [System.Runtime.InteropServices.MarshalAs(System.Runtime.InteropServices.UnmanagedType.ByValTStr, SizeConst = 128)]
  public string szPathName;
}

Tips & Tricks:

Please add some!

VB.NET Signature:

Private Declare Function OpenFile Lib "kernel32.dll" (ByVal lpFileName As String, ByRef lpReOpenBuff As OFSTRUCT, ByVal uStyle As Long) As Long

User-Defined Types:

<System.Runtime.InteropServices.StructLayout(LayoutKind.Sequential)> _
Public Structure OFSTRUCT
    Public cBytes As Byte
    Public fFixedDisc As Byte
    Public nErrCode As UInt16
    Public Reserved1 As UInt16
    Public Reserved2 As UInt16
    <System.Runtime.InteropServices.MarshalAs(System.Runtime.InteropServices.UnmanagedType.ByValTStr, SizeConst:=128)> _
    Public szPathName As String
End Structure

Notes:

None.

Tips & Tricks:

Please add some!

Sample Code:

        const UInt32 STANDARD_RIGHTS_REQUIRED = 0x000F0000;
        const UInt32 SECTION_QUERY = 0x0001;
        const UInt32 SECTION_MAP_WRITE = 0x0002;
        const UInt32 SECTION_MAP_READ = 0x0004;
        const UInt32 SECTION_MAP_EXECUTE = 0x0008;
        const UInt32 SECTION_EXTEND_SIZE = 0x0010;
        const UInt32 SECTION_ALL_ACCESS = (STANDARD_RIGHTS_REQUIRED|SECTION_QUERY|
            SECTION_MAP_WRITE |      
            SECTION_MAP_READ |      
            SECTION_MAP_EXECUTE |    
            SECTION_EXTEND_SIZE);
        const UInt32 FILE_MAP_ALL_ACCESS = SECTION_ALL_ACCESS;
        private IntPtr hHandle;
        private IntPtr pBuffer;
        unsafe public void Attach(string SharedMemoryName, UInt32 NumBytes)
        {
            if (IntPtr.Zero != hHandle) return;
            hHandle = OpenFileMapping(FILE_MAP_ALL_ACCESS, false, SharedMemoryName);
            if (IntPtr.Zero == hHandle) return;
            pBuffer = MapViewOfFile(hHandle, FILE_MAP_ALL_ACCESS, 0, 0, &NumBytes);
        }
        public void Detach()
        {
            if (IntPtr.Zero != hHandle)
            {
                CloseHandle(hHandle); //fair to leak if can't close
                hHandle = IntPtr.Zero;
            }
            pBuffer = IntPtr.Zero;
            lBufferSize = 0;
        }
Private Const OF_EXIST As Long = &H4000
Private Const OF_ERROR As Long = -1
Private Const OFS_MAXPATHNAME As Long = 128

Public Function FileExists(ByVal sFile As String) As Boolean
    Dim lRetVal As Long
    Dim of As OFSTRUCT

Alternative Managed API:

Do you know one? Please contribute it!

    lRetVal = OpenFile(sFile, of, OF_EXIST)
    If lRetVal <> OF_ERROR Then
        FileExists = True
    Else
        FileExists = False
    End If
End Function

Alternative Managed API:

Do you know one? Please contribute it!

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