關於 Shared Memory 的兩三事

using System;

using System.Collections.Generic;

using System.IO;

using System.IO.MemoryMappedFiles;

using System.Linq;

using System.Text;

using System.Threading;

namespace ProcessA

{

    class Program

    {

        static void Main(string[] args)

        {

            //REF: https://msdn.microsoft.com/en-us/library/dd267552(v=vs.110).aspx

            using (MemoryMappedFile mmf = MemoryMappedFile.CreateNew("DARKTHREAD", 1024))

            {

                bool mutexCreated;

                Mutex mutex = new Mutex(true, "DarkthreadSharedMem", out mutexCreated);

                using (var stream = mmf.CreateViewStream()) {

                    byte[] msg = Encoding.UTF8.GetBytes("Hello, World!");

                    using (BinaryWriter bw = new BinaryWriter(stream))

                    {

                        bw.Write(msg.Length); //先寫Length

                        bw.Write(msg); //再寫byte[]

                    }

                }

                mutex.ReleaseMutex();

                Console.Write("操作 Process B 進行讀取及回應，完成後按Enter");

                Console.ReadLine();

                mutex.WaitOne();

                using (MemoryMappedViewStream stream = mmf.CreateViewStream(512, 512))

                {

                    using (var br = new BinaryReader(stream))

                    {

                        //先讀取長度，再讀取内容

                        var len = br.ReadInt32();

                        var msg = Encoding.UTF8.GetString(br.ReadBytes(len), 0, len);

                        Console.WriteLine($"回應＝{msg}");

                    }

                }

                mutex.ReleaseMutex();

                Console.ReadLine();

            }

        }

    }

}

using System;

using System.Collections.Generic;

using System.IO;

using System.IO.MemoryMappedFiles;

using System.Linq;

using System.Text;

using System.Threading;

namespace ProcessB

{

    class Program

    {

        static void Main(string[] args)

        {

            try

            {

                Console.Write("按 Enter 開始讀取及回應…");

                Console.ReadLine();

                using (MemoryMappedFile mmf = MemoryMappedFile.OpenExisting("DARKTHREAD"))

                {

                    Mutex mutex = Mutex.OpenExisting("DarkthreadSharedMem");

                    mutex.WaitOne();                    

                    using (MemoryMappedViewStream stream = mmf.CreateViewStream(0, 0))

                    {

                        using (var br = new BinaryReader(stream))

                        {

                            //先讀取長度，再讀取内容

                            var len = br.ReadInt32();

                            var word = Encoding.UTF8.GetString(br.ReadBytes(len), 0, len);

                            Console.WriteLine($"訊息＝{word}");

                        }

                    }

                    using (MemoryMappedViewStream stream = mmf.CreateViewStream(512, 512))

                    {

                        using (var bw = new BinaryWriter(stream))

                        {

                            var msg = Encoding.UTF8.GetBytes("朕知道了");

                            bw.Write(msg.Length);

                            bw.Write(msg);

                        }

                    }

                    mutex.ReleaseMutex();

                }

                Console.ReadLine();

            }

            catch (FileNotFoundException)

            {

                Console.WriteLine("Memory-mapped file does not exist.");

            }

        }

    }

}