Rimuovere variabile condivisa tra 2 o piu applicazioni - C++ dll

#include "stdafx.h"

#include "SharedMemorySrv.h"
#include "tchar.h"
#include "stdio.h"

extern HANDLE m_hFileMMF, m_pViewMMFFile, hMutex;

class CMutex
{

public:
  CMutex()
  {
    if(!hMutex){
      hMutex = CreateMutex(
        NULL,              // default security attributes
        FALSE,             // initially not owned
        L"Global\\MMFMutex");             // unnamed mutex
    }

    WaitForSingleObject(  hMutex, INFINITE);  

  }

  ~CMutex()
  {
    ReleaseMutex(hMutex);
  }

};

void SetRecordCount(int value)
{
  TCHAR* record = (TCHAR*)m_pViewMMFFile;
  swprintf_s(record, MAX_PATH, L"RECCNT=%d#", value);
}

extern "C" int GetRecordCount()
{
  TCHAR* record = (TCHAR*)m_pViewMMFFile;
  TCHAR temp[MAX_PATH];

  int recordCount = -1;

  TCHAR seps[]   = L"=#";
  TCHAR *token1 = NULL;
  TCHAR *next_token1 = NULL;

  _tcscpy_s(temp, MAX_PATH, record);

  token1 = _tcstok_s ( temp, seps, &next_token1);

  if(token1 && _tcscmp(token1, _T("RECCNT")) == 0)
  {
    token1 = _tcstok_s ( NULL, seps, &next_token1);

    recordCount = _ttoi(token1);
  }else
  {
    recordCount = 1;
    SetRecordCount(1);
  }

  return recordCount;
}


int nRecordCount = -1;

extern "C" void RemoveValue(TCHAR* key)
{
  CMutex mutex;

  TCHAR* record = (TCHAR*)m_pViewMMFFile;

  TCHAR temp[MAX_PATH];

  nRecordCount = GetRecordCount();

  record+=MAX_PATH;

  //Try to look. If found, break out of for loop
  //Compact the memory immediately immediately
  //If you get time, strongly advice you to do a lazy compaction
  bool isRecordFound = false;
  int i;
  for(i= 1; i< nRecordCount; i++,record+=MAX_PATH)
  {
    TCHAR seps[]   = L"=#";
    TCHAR *token1 = NULL;
    TCHAR *next_token1 = NULL;

    _tcscpy_s(temp, MAX_PATH, record);

    token1 = _tcstok_s (temp, seps, &next_token1);


    if(_tcscmp(token1, key) == 0)
    {
      isRecordFound = true;
      break;
    }
  }

  //start moving the records 
  for(; i< nRecordCount-1; i++, record+=MAX_PATH)
  {
    TCHAR* nextRecord = record + MAX_PATH;
    _tcscpy_s(record, MAX_PATH, nextRecord);
  }
}



TCHAR* IfExists(TCHAR* key, TCHAR** value = NULL)
{
  TCHAR* record = (TCHAR*)m_pViewMMFFile;

  TCHAR temp[MAX_PATH];

  nRecordCount = GetRecordCount();

  record+=MAX_PATH;
  for(int i=1; i< nRecordCount; i++,record+=MAX_PATH)
  {
    TCHAR seps[]   = L"=#";
    TCHAR *token1 = NULL;
    TCHAR *next_token1 = NULL;

    _tcscpy_s(temp, MAX_PATH, record);

    token1 = _tcstok_s ( temp, seps, &next_token1);

    if(_tcscmp(token1, key) == 0)
    {
      token1 = _tcstok_s ( NULL, seps, &next_token1);

      //return a copy of the value
      if(value!=NULL)
      {
        int len = _tcslen(token1)+1;
        *value = new TCHAR(len);
        _tcscpy_s(*value, len, token1);
      }

      return record;
    }
  }

  return NULL;
}

extern "C" TCHAR* GetValue(TCHAR* key)
{
  TCHAR* sRetVal = new TCHAR[MAX_PATH];

  CMutex mutex;  

  TCHAR* data = NULL;

  if(m_pViewMMFFile)
  {
    IfExists(key, &data);
  }

  return data;
}


extern "C" void SetValue(TCHAR* key, TCHAR* value)
{
  CMutex mutex;  

  if(m_pViewMMFFile )
  {
    if(value == NULL)
    {
      RemoveValue(key);
    }
    else
    {
      TCHAR* data = IfExists(key);
      if(data == NULL)
      {
        data = new TCHAR[MAX_PATH];
        swprintf_s(data, MAX_PATH, L"%s=%s#", key, value);

        //Add to end of the MMF
        TCHAR* record = (TCHAR*)m_pViewMMFFile;
        record += MAX_PATH*nRecordCount;
        nRecordCount++;

        SetRecordCount(nRecordCount);

        _tcscpy_s(record, MAX_PATH, data);
        delete data;
      }
      else
      {
        //Replace existing
        swprintf_s(data, MAX_PATH, L"%s=%s#", key, value);
      }
    }
  }
}

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Runtime.InteropServices;

namespace SharedMemoryClient
{
    public partial class Form1 : Form
    {

        [DllImport("Test.dll", CallingConvention = CallingConvention.Cdecl)]
        extern static int GetRecordCount();

        [DllImport("Test.dll", CallingConvention = CallingConvention.Cdecl)]
        extern static void SetValue(
            [MarshalAs(UnmanagedType.LPTStr)] string key,
            [MarshalAs(UnmanagedType.LPTStr)] string value);

        [DllImport("Test.dll", CallingConvention = CallingConvention.Cdecl)]
        extern static IntPtr GetValue([MarshalAs(UnmanagedType.LPTStr)]string key);

        [DllImport("Test.dll", CallingConvention = CallingConvention.Cdecl)]
        extern static IntPtr RemoveValue([MarshalAs(UnmanagedType.LPTStr)]string key);

        public Form1()
        {
            InitializeComponent();
        }

        private void SetVar_Btn_Click(object sender, EventArgs e)
        {
            //Set
            SetValue(VarName_TxtBox.Text, VarValue_TxtBox.Text);
            UpdateRecordCount(null, null);
        }

        private void GetVar_Btn_Click(object sender, EventArgs e)
        {
            //Get
            //StringBuilder sb = new StringBuilder();
            IntPtr intPtr = GetValue(VarName_TxtBox.Text);
            VarValue_TxtBox.Text = Marshal.PtrToStringUni(intPtr);
            UpdateRecordCount(null, null);
        }

        private void UpdateRecordCount(object sender, EventArgs e)
        {
            linkLabel1.Text = "Count = " + GetRecordCount().ToString();
        }

        private void Remove_Btn_Click(object sender, EventArgs e)
        {
            RemoveValue(VarName_TxtBox.Text);

            MessageBox.Show(VarName_TxtBox.Text.ToString() + ": removed !");

            UpdateRecordCount(null, null);
        }
    }
}