GetProcAddress

C# Signature:

[DllImport("kernel32", CharSet=CharSet.Ansi, ExactSpelling=true, SetLastError=true)]
static extern IntPtr GetProcAddress(IntPtr hModule, string procName);

VB.NET Signature:

<DllImport("kernel32.dll", SetLastError:=True, CharSet:=CharSet.Ansi, ExactSpelling:=True)> _
Private Function GetProcAddress(ByVal hModule As IntPtr, ByVal procName As String) As UIntPtr
End Function

VB Signature:

Private Declare Function GetProcAddress Lib "kernel32" (ByVal hModule As Integer, ByVal lpProcName As String) As Integer

C++ Signature:

[DllImport("KERNEL32.DLL", CharSet=CharSet::Ansi, EntryPoint="GetProcAddress", ExactSpelling=true)]
static IntPtr GetProcAddress(IntPtr hModule, String^ lpProcName);

Boo Signature:

[DllImport("kernel32.dll", CharSet : CharSet.Ansi, ExactSpelling : true)]
static def GetProcAddress(hModule as IntPtr, procName as string) as IntPtr:
     pass

Tips & Tricks:

internal static class UnsafeNativeMethods {
   [DllImport("kernel32", CharSet=CharSet.Ansi, ExactSpelling=true, SetLastError=true)]
   internal static extern IntPtr GetProcAddress(IntPtr hModule, string procName );
}

internal delegate int DllRegisterServerInvoker();

// code snippet in a method somewhere, error checking omitted
IntPtr fptr = UnsafeNativeMethods.GetProcAddress( hModule, "DllRegisterServer" );
DllRegisterServerInvoker drs = (DllRegisterServerInvoker) Marshal.GetDelegateForFunctionPointer( fptr, typeof(DllRegisterServerInvoker) );
drs(); // call via a function pointer

Tips & Tricks:

[DllImport("kernel32", SetLastError = true, EntryPoint = "GetProcAddress")]
static extern IntPtr GetProcAddressOrdinal(IntPtr hModule, IntPtr procName);

Sample Code:

static HMODULE hDLL;
typedef HRESULT (STDAPICALLTYPE * LPFNTEST) (void);
LPFNTEST _pfnTest;

hDLL = LoadLibrary("MyDLL.dll");
_pfnTest = (LPFNTEST)::GetProcAddress(hDLL, "Test");