WIndowsの共有メモリを使う

単純なサンプル

//2019-05-03 gpsnmeajp
//These codes are licensed under CC0.
//http://creativecommons.org/publicdomain/zero/1.0/deed.ja
#include <windows.h>
#include <stdio.h>
#include <conio.h>

int main(void){
    //--------------共有メモリ------------
    DWORD MaxSizeLow = 100;
    //ハンドルのオープン
    HANDLE FileHandle = CreateFileMappingA(INVALID_HANDLE_VALUE, NULL, PAGE_READWRITE, 0, MaxSizeLow, "MEM_SEND");
    //ハンドルのオープンに失敗
    if (FileHandle == NULL)
    {
        return -1;
    }

    //メモリのマッピング
    LPVOID Mapping = MapViewOfFile(FileHandle, FILE_MAP_ALL_ACCESS, 0, 0, 0);
    //マッピングに失敗
    if (Mapping == NULL)
    {
        CloseHandle(FileHandle);
        return -1;
    }
    char *SharedRam = (char*)Mapping;

    SharedRam[0] = '\0';
    while (!_kbhit())
    {
        printf("<-%s\n", SharedRam);
        //Sleep(100);
    }

    //メモリの開放
    UnmapViewOfFile(Mapping);
    CloseHandle(FileHandle);


    return 0;
}

クラス化

//2019-05-04 gpsnmeajp
//These codes are licensed under CC0.
//http://creativecommons.org/publicdomain/zero/1.0/deed.ja

#include <windows.h>
#include <stdio.h>
#include <conio.h>

//----------共有メモリ-----------

class SharedMemory{
private:
    DWORD SharedMemorySize = 16 * 1024; //16KB
    HANDLE SharedMemoryHandle = NULL;
    LPVOID SharedMemoryBuffer = NULL;

public:
    SharedMemory()
    {
    }

    SharedMemory(const char* Pipename)
    {
        printf(Pipename);
        open(Pipename);
    }

    ~SharedMemory()
    {
        close();
    }

    LPVOID get_pointer(){
        return SharedMemoryBuffer;
    }

    bool is_open(){
        return (SharedMemoryBuffer != NULL) && (SharedMemoryHandle != NULL);
    }

    void set_size(DWORD _SharedMemorySize)
    {
        SharedMemorySize = _SharedMemorySize;
    }

    DWORD get_size()
    {
        return SharedMemorySize;
    }

    void print(const char *fmt, ...){
        va_list va;
        va_start(va, fmt);
        vsprintf_s((char*)SharedMemoryBuffer, SharedMemorySize-1, fmt, va);
        va_end(va);
    }

    void open(const char* Pipename){
        //もし仮にすでに開いている場合閉じる
        close();

        //ハンドルのオープン
        SharedMemoryHandle = CreateFileMappingA(INVALID_HANDLE_VALUE, NULL, PAGE_READWRITE, 0, SharedMemorySize, Pipename);
        //ハンドルのオープンに失敗
        if (SharedMemoryHandle == NULL)
        {
            return;
        }

        //メモリのマッピング
        SharedMemoryBuffer = MapViewOfFile(SharedMemoryHandle, FILE_MAP_ALL_ACCESS, 0, 0, 0);
        //マッピングに失敗
        if (SharedMemoryBuffer == NULL)
        {
            //先に開いたハンドルを閉じる
            CloseHandle(SharedMemoryHandle);
            return;
        }
    }

    void close(){
        if (SharedMemoryBuffer != NULL){
            UnmapViewOfFile(SharedMemoryBuffer);
        }
        if (SharedMemoryHandle != NULL){
            CloseHandle(SharedMemoryHandle);
        }
    }
};

int main(void){
    SharedMemory comm("pip1");
    if (!comm.is_open())
    {
        return -1;
    }

    char *SharedRam = (char*)comm.get_pointer();

    int i = 0;
    while (!_kbhit())
    {
        comm.print("Hello World %d", i);
        printf("%s\n", SharedRam);
        i++;
    }

    return 0;
}

C＃

MS公式サンプルの改造

//https://docs.microsoft.com/ja-jp/dotnet/api/system.io.memorymappedfiles.memorymappedfile?view=netframework-4.8

using System;
using System.IO;
using System.Text;
using System.IO.MemoryMappedFiles;
using System.Runtime.InteropServices;


namespace ConsoleApp1
{
    class Program
    {
        static void Main(string[] args)
        {
            using (var mmf = MemoryMappedFile.CreateOrOpen(@"pip1", 1024 * 16))
            {
                using (var accessor = mmf.CreateViewAccessor(0, 0))
                {
                    while (!Console.KeyAvailable)
                    {
                        byte[] buf = new byte[1024 * 16];
                        accessor.ReadArray(0, buf, 0, 1024 * 16);

                        int count = 0;
                        for (int i = 0; i < buf.Length; i++)
                        {
                            if (buf[i] == '\0')
                            {
                                Array.Resize<byte>(ref buf, i); //切り詰め
                                break;
                            }
                        }

                        string s = Encoding.ASCII.GetString(buf);
                        Console.WriteLine(s);
                    }
                }
            }
        }
    }
}