C# Signature:

    [DllImport("kernel32.dll")]
    static extern int VirtualQueryEx(IntPtr hProcess, IntPtr lpAddress, out MEMORY_BASIC_INFORMATION lpBuffer, uint dwLength);

C# User-Defined Types:

MEMORY_BASIC_INFORMATION

    [StructLayout(LayoutKind.Sequential)]
    public struct MEMORY_BASIC_INFORMATION
    {
    public IntPtr BaseAddress;
    public IntPtr AllocationBase;
    public uint AllocationProtect;
    public IntPtr RegionSize;
    public uint State;
    public uint Protect;
    public uint Type;
    }

c# usefull Flags for MEMORY_BASIC_INFORMATION

Flags

    public enum AllocationProtect : uint
    {
    PAGE_EXECUTE = 0x00000010,
    PAGE_EXECUTE_READ = 0x00000020,
    PAGE_EXECUTE_READWRITE = 0x00000040,
    PAGE_EXECUTE_WRITECOPY = 0x00000080,
    PAGE_NOACCESS = 0x00000001,
    PAGE_READONLY = 0x00000002,
    PAGE_READWRITE = 0x00000004,
    PAGE_WRITECOPY = 0x00000008,
    PAGE_GUARD = 0x00000100,
    PAGE_NOCACHE = 0x00000200,
    PAGE_WRITECOMBINE = 0x00000400
    }

Notes:

VirtualQueryEx returns 0 on failure.

Tips & Tricks:

Please add some!

Sample Code:

The following code demonstrates how to list all regions within a process' memory address.

long MaxAddress = 0x7fffffff;
long address = 0;
do
{
     MEMORY_BASIC_INFORMATION m;
     int result = VirtualQueryEx(System.Diagnostics.Process.GetCurrentProcess().Handle, (IntPtr)address, out m, (uint)Marshal.SizeOf(typeof(MEMORY_BASIC_INFORMATION)));
     Console.WriteLine("{0}-{1} : {2} bytes result={3}", m.BaseAddress, (uint)m.BaseAddress + (uint)m.RegionSize - 1, m.RegionSize, result);
     if (address == (long)m.BaseAddress + m.RegionSize)
     break;
     address = (long)m.BaseAddress + m.RegionSize;
} while (address <= MaxAddress);

Alternative Managed API:

Do you know one? Please contribute it!