using System;

using System.Collections.Generic;
using System.Windows.Forms;
using System.Runtime.InteropServices;

namespace RTTPrj
{
    static class Program
    {
        [DllImport("coredll.Dll")]
        private static extern int GetLastError();

        [DllImport("coredll.Dll")]
        private static extern int ReleaseMutex(IntPtr hMutex);

        [DllImport("coredll.Dll")]
        private static extern IntPtr CreateMutex(SECURITY_ATTRIBUTES lpMutexAttributes, bool bInitialOwner, string lpName);

        [StructLayout(LayoutKind.Sequential)]
        public class SECURITY_ATTRIBUTES
        {
            public int nLength;
            public int lpSecurityDescriptor;
            public int bInheritHandle;
        }
        const int ERROR_ALREADY_EXISTS = 0183;

        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        [MTAThread]
        static void Main()
        {
            #region Api_Call CreateMutex;
            IntPtr hMutex;
            hMutex = CreateMutex(null, false, "RTTPrj");
            if (GetLastError() != ERROR_ALREADY_EXISTS)
            {
                Application.Run(new Form1());
            }
            else
            {
                MessageBox.Show("Allow run a program simultaneously!!");
                ReleaseMutex(hMutex);
            }
            #endregion
        }

    }
}