Public Declare Ansi Sub DtcGetTransactionManager Lib "xolehlp.dll" (ByVal hostName As String, ByVal tmName As String, ByVal iid As Guid, ByVal dwReserved1 As Integer, ByVal wReserved2 As Short, ByVal pvReserved As Integer, ByRef ppv As Integer)

Declare Function WNetAddConnection2 Lib "mpr.dll" (ByRef netResource As _

                           ByRef lpNetResource As NETRESOURCE, _

Public Shared Function WNetEnumResource(hEnum As IntPtr, ByRef lpcCount As Integer, lpBuffer As IntPtr, ByRef lpBufferSize As UInteger) As UInteger

    Public Function WNetEnumResource(ByVal hEnum As IntPtr, ByRef lpcCount As Integer, ByVal lpBuffer As IntPtr, ByRef lpBufferSize As Integer) As Integer

    Public Function WNetOpenEnum(ByVal dwScope As RESOURCE_SCOPE, ByVal dwType As RESOURCE_TYPE, ByVal dwUsage As RESOURCE_USAGE, ByRef lpNetResource As NETRESOURCE, ByRef lphEnum As IntPtr) As Integer

    Public Function GetNetworkDrives(ByRef o As NETRESOURCE, ByRef networkDriveCollection As List(Of String)) As Boolean

    Public Function GetNetworkComputers(ByRef o As NETRESOURCE, ByRef networkComputersCollection As List(Of String)) As Boolean

    Public Function WNETOE(ByRef o As NETRESOURCE, ByRef resourceCollection As List(Of String)) As Boolean

                      ByRef length As Integer) As Integer

    Declare Function WNetGetConnection Lib "mpr.dll" Alias "WNetGetConnectionA" (ByVal localName As String, ByVal remoteName As System.Text.StringBuilder, ByRef length As Integer) As Integer

    ByVal remoteName As System.Text.StringBuilder, ByRef length As Integer) As Integer

                      ByRef length As Integer) As Integer

Declare Function WNetGetLastError Lib "mpr.dll" Alias "WNetGetLastErrorA" (ByRef lpError As Integer, ByVal lpErrorBuf As String, ByVal nErrorBufSize As Integer, ByVal lpNameBuf As String, ByVal nNameBufSize As Integer) As Integer

Public Shared Function WNetOpenEnum(dwScope As ResourceScope, dwType As ResourceType, dwUsage As ResourceUsage, lpNetResource As NetResource, ByRef lphEnum As IntPtr) As UInteger

    <Out> ByRef perceivedType As PerceivedType, _

    <Out> ByRef perceivedFlags As PerceivedFlags, _

Private Shared Function AssocQueryString(ByVal flags As UInteger, ByVal str As UInteger, ByVal pszAssoc As String, ByVal pszExtra As String, ByVal pszOut As Text.StringBuilder, ByRef pcchOut As UInteger) As UInteger

     ByRef pathLength As System.UInt32, _

     ByRef urlLength As System.UInt32, _

   <[In]> ByRef iidResult As Guid, <MarshalAs(UnmanagedType.Interface), Out> ByRef _

                           ByRef lplpMessageFilter As IMessageFilter) As Integer

Private Declare Function CreateFileMoniker Lib "ole32.dll" (ByVal lpszPathName As String, ByRef ppmk As IMoniker) As Integer

                              <Out()> ByRef ppLkbyt As IlockBytes) _

    Declare Function CreateStreamOnHGlobal Lib "ole32" (ByVal hGlobal As IntPtr, ByVal fDeleteOnRelease As Boolean, ByRef ppstm As UCOMIStream) As Long

    <[In]()> ByRef FMTID As Guid, _

    ByRef ppUnk As Object, _

    ByRef ppUnk As Object, _

    <Out()> ByRef FMTID As Guid) As Integer

Declare Function HidD_FreePreparsedData Lib "hid.dll" (ByRef PreparsedData As Integer) As Boolean

For VB - Must include "Imports Microsoft.Win32.SafeHandles". The reportBuffer parameter must be ByVal. The call will fail with windows system error 23 if it is ByRef.

Declare Function GetGuid Lib dll" (ByRef Guid Guid) As void

Public Declare Auto Function mciGetErrorString Lib "winmm.dll" (ByVal errorCode As Integer, ByRef errorText As StringBuilder, ByVal errorTextSize As Integer) As Integer

Declare Ansi Function mciSendString Lib "winmm.dll" Alias "mciSendStringA" (ByVal command As String, ByRef buffer As StringBuilder, ByVal bufferSize As Integer, ByVal hWndCallback As IntPtr) As Integer

Protected Overrides Sub WndProc(ByRef m As System.Windows.Forms.Message)

Declare Function midiOutClose Lib "winmm.dll" (ByRef phMidiOut As IntPtr) As Uinteger

    <DllImport("winmm.dll")> Shared Function midiOutOpen(ByRef lphMidiOut As IntPtr, ByVal uDeviceID As UInteger, ByVal dwCallback As IntPtr, ByVal dwInstance As IntPtr, ByVal dwFlags As UInteger) As UInteger

Declare Function mixerGetControlDetails Lib "winmm.dll" (<MarshalAs(UnmanagedType.I4)> ByVal hmxobj As Integer, ByRef pmxcd As MIXERCONTROLDETAILS, ByVal fdwDetails As Integer) As Integer

   Private Shared Function MixerGetDevCaps(ByVal mixerId As Integer, ByRef mixerCaps As MixerCaps, ByVal mixerCapsSize As Integer) As UInteger

Shared Function mixerGetID(<MarshalAs(UnmanagedType.I4)> ByVal hmxobj As Integer, ByRef puMxId As UInteger, ByVal fdwId As MixerFlags) As MMRESULT

   ByRef pmxlc As MIXERLINECONTROLS, fdwControls As Integer) As Integer

Shared Function mixerGetLineInfo(<MarshalAs(UnmanagedType.I4)> ByVal hmxobj As Integer, ByRef pmxl As MIXERLINE, ByVal fdwInfo As MixerFlags) As MMRESULT

Declare Function mixerOpen Lib "winmm.dll" (ByRef phmx As IntPtr, ByVal pMxId As UInteger, ByVal dwCallback As IntPtr, ByVal dwInstance As IntPtr, ByVal fdwOpen As UInteger) As Integer

Declare Function timeGetDevCaps Lib "winmm.dll" (ByRef lpTimeCaps As TimeCaps, ByVal uSize As UInt32) As UInt32

Shared Function waveInAddBuffer(<MarshalAs(UnmanagedType.I4)> ByVal hwi As Integer, ByRef pwh As WAVEHDR, ByVal cbwh As UInteger) As MMRESULT

When recording waveform audio, usually buffers are allocated with unmanaged functions and kept in an IntPtr() array; for this reason the function is provided in two versions, one processing a WAVEHDR ByRef and the other working with an IntPtr.

Shared Function waveInUnprepareHeader(<MarshalAs(UnmanagedType.I4)> ByVal hwi As Integer, ByRef pwh As WAVEHDR, ByVal cbwh As UInteger) As MMRESULT

Declare Auto Function waveOutGetDevCaps Lib "winmm.dll" (ByVal uDeviceID as Integer, ByRef lpCaps As WAVEOUTCAPS, _

Declare Function waveOutGetVolume Lib "winmm.dll" (ByVal hwo As IntPtr, ByRef dwVolume As UInteger) As Integer

Declare Function waveOutOpen Lib "winmm.dll" Alias "waveOutOpen" (ByRef phwi As IntPtr, ByVal uDeviceID As IntPtr, ByRef pwfx As WAVEFORMATEX, ByVal dwCallback As IntPtr, ByVal dwCallbackInstance As IntPtr, ByVal fdwOpen As WAVE_FLAGS) As MMSYSERR

Declare Function waveOutOpen Lib "winmm.dll" Alias "waveOutOpen" (ByRef phwi As IntPtr, ByVal uDeviceID As IntPtr, ByRef pwfx As WAVEFORMATEXTENSIBLE, ByVal dwCallback As IntPtr, ByVal dwCallbackInstance As IntPtr, ByVal fdwOpen As WAVE_FLAGS) As MMSYSERR

    <Out()> ByRef SiteNameBuffer As IntPtr) As UInt32

Declare Function LsaQueryInformationPolicy Lib "Advapi32.dll" (ByVal PolicyHandle As IntPtr, ByVal InformationClass As UInteger, ByRef Buffer As IntPtr) As UInteger

Changed VB.NET Signature from "ByRef buffer" to "ByVal buffer". With ByRef you get a significant memory leak, with ByVal everything is fine.

        ByRef Buffer As IntPtr, _

        ByRef EntriesRead As Integer, _

        ByRef ResumeHandle As Integer) As Integer

    ByRef buffer As IntPtr) As Integer

Declare Unicode Function NetDfsGetInfo Lib "NETAPI32.DLL" (ByVal DfsEntryPath As String, ByVal ServerName As String, ByVal ShareName As String, ByVal Level As Integer, ByRef Buffer As IntPtr) As Integer

    ByRef bufptr As IntPtr, _

    ByRef entriesread As Integer, _

    ByRef totalentries As Integer, _

  Private Shared Function NetGetDCName(ByVal serverName As String, ByVal domainName As String, ByRef buffer As IntPtr) As NetApiStatus

    ByRef lpNameBuffer As IntPtr, _

    ByRef bufferType As NETSETUP_JOIN_STATUS) _

        ByRef lpNameBuffer As IntPtr, _

        ByRef bufferType As NETSETUP_JOIN_STATUS) _

    ByRef entriesRead As Integer, _

    ByRef Buffer As Long) As Integer

     ByRef OptionsSupported As NetSupportOption) _

    ByVal UncServerName As String, ByRef BufferPtr As IntPtr) As Integer

    Friend Shared Function NetScheduleJobAdd(ByVal Servername As String, ByVal Buffer As IntPtr, ByRef JobId As Integer) As Integer

    ByRef bufptr As IntPtr, _

    ByRef entriesread As Integer, _

    ByRef TotalEntries As Integer, _

    ByVal Level As Integer, ByRef ptrBuff As IntPtr) As Integer

        ByRef bufptr As IntPtr, _

        ByRef entriesread As Integer, _

        ByRef totalentries As Integer, _

        ByRef resume_handle As Integer) As Integer

            ByRef buf As SHARE_INFO_2, _

            ByRef parm_err As Integer) As Integer

            ByRef BufPtr As IntPtr,

            ByRef entriesread As Integer, _

            ByRef totalentries As Integer, _

            ByRef resume_handle As Integer) As Integer

        ByRef BufPtr As IntPtr, _

        ByRef entriesread As Integer, _

        ByRef totalentries As Integer, _

        ByRef resume_handle As Integer) As Integer

        ByRef BufPtr As IntPtr, _

        ByRef entriesread As Integer, _

        ByRef totalentries As Integer, _

        ByRef resume_handle As Integer) As Integer

    ByRef BufPtr As IntPtr) As Integer

      (ByRef buffer As IntPtr) As Long

            ByRef BufPtr As IntPtr) As Integer

    ByRef BufPtr As IntPtr) As Integer

    (ByRef buffer As IntPtr) As Long

    ByRef Buf As IntPtr, _

    ByRef EntriesRead As Integer, _

    ByRef TotalEntries As Integer, _

    ByRef resumeHandle As IntPtr) As NET_API_STATUS

    ByRef buf As USER_INFO_1, _

    ByRef param_error As Integer) As Integer

    ByRef buf As USER_INFO_1, _

    ByRef param_error As Integer) As Integer

    ByRef bufptr As IntPtr, _

    ByRef entriesread As Integer, _

    ByRef totalentries As Integer, _

    ByRef resume_handle As Integer) As Integer