C# Signature:

[DllImport("kernel32.dll", SetLastError=true, ExactSpelling=true)]
static extern IntPtr VirtualAllocEx(IntPtr hProcess, IntPtr lpAddress,
   IntPtr dwSize, AllocationType flAllocationType, MemoryProtection flProtect);

VB.NET Signature:

<DllImport("kernel32.dll", SetLastError:=True, ExactSpelling:=True)> _
Private Function VirtualAllocEx(ByVal hProcess As IntPtr, ByVal lpAddress As IntPtr, _
     ByVal dwSize As IntPtr, ByVal flAllocationType As UInteger, _
     ByVal flProtect As UInteger) As IntPtr
End Function

Boo Signature:

[DllImport("kernel32.dll", SetLastError : true, ExactSpelling : true)]
static def VirtualAllocEx(hProcess as IntPtr, lpAddress as IntPtr, dwSize as IntPtr, flAllocationType as AllocationType, flProtect as MemoryProtection) as IntPtr:
     pass
[DllImport("kernel32.dll", SetLastError=true)]
static extern UIntPtr VirtualAlloc(UIntPtr lpAddress, UIntPtr dwSize,
   AllocationType flAllocationType, MemoryProtection flProtect);

User-Defined Types:

[Flags]
public enum AllocationType
{
     Commit = 0x1000,
     Reserve = 0x2000,
     Decommit = 0x4000,
     Release = 0x8000,
     Reset = 0x80000,
     Physical = 0x400000,
     TopDown = 0x100000,
     WriteWatch = 0x200000,
     LargePages = 0x20000000
}
  [Flags()]
  public enum AllocationType:uint
  {
    COMMIT=0x1000,
    RESERVE=0x2000,
    RESET=0x80000,
    LARGE_PAGES=0x20000000,
    PHYSICAL=0x400000,
    TOP_DOWN=0x100000,
    WRITE_WATCH=0x200000
  }

  [Flags()]
  public enum MemoryProtection:uint
  {
    EXECUTE=0x10,
    EXECUTE_READ=0x20,
    EXECUTE_READWRITE=0x40,
    EXECUTE_WRITECOPY=0x80,
    NOACCESS=0x01,
    READONLY=0x02,
    READWRITE=0x04,
    WRITECOPY=0x08,
    GUARD_Modifierflag=0x100,
    NOCACHE_Modifierflag = 0x200,
    WRITECOMBINE_Modifierflag = 0x400
  }

None.

[Flags]
public enum MemoryProtection
{
     Execute = 0x10,
     ExecuteRead = 0x20,
     ExecuteReadWrite = 0x40,
     ExecuteWriteCopy = 0x80,
     NoAccess = 0x01,
     ReadOnly = 0x02,
     ReadWrite = 0x04,
     WriteCopy = 0x08,
     GuardModifierflag = 0x100,
     NoCacheModifierflag = 0x200,
     WriteCombineModifierflag = 0x400
}

Notes:

None.

[Flags]
enum AllocationType:
     Commit = 0x1000
     Reserve = 0x2000
     Decommit = 0x4000
     Release = 0x8000
     Reset = 0x80000
     Physical = 0x400000
     TopDown = 0x100000
     WriteWatch = 0x200000
     LargePages = 0x20000000

[Flags]
enum MemoryProtection:
     Execute = 0x10
     ExecuteRead = 0x20
     ExecuteReadWrite = 0x40
     ExecuteWriteCopy = 0x80
     NoAccess = 0x01
     ReadOnly = 0x02
     ReadWrite = 0x04
     WriteCopy = 0x08
     GuardModifierflag = 0x100
     NoCacheModifierflag = 0x200
     WriteCombineModifierflag = 0x400

Notes:

None.

Tips & Tricks:

You can get the dwSize in C# with Marshal.SizeOf(typeof(TYPE))

Marshal.AllocHGlobal(size) is a managed alternative api. But you must use VirtualAlloc directly, is you need special accessrights or protection.

Sample Code:

Please add some!

Alternative Managed API:

The ManagedWindowsApi project (http://mwinapi.sourceforge.net) provides a ProcessMemoryChunk class to allocate and access memory of a different process.

See Also:

VirtualAllocEx

VirtualFree

Alternative Managed API:

Do you know one? Please contribute it!

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