Windows multi-threaded programming entry notes

Each time the processing parallel tasks, if you want to wait for user input or rely on external (e.g., in response to the controller Hang Chan), should be similar for the operation creates a separate thread, so that our program will not hang unresponsive.
Static and dynamic library
static library refers to the pre-compiled program is run on the database, such as #include behavior;
dynamic link library refers to the program runtime libraries, such as user32.dll.

First, the event handler and the message passing interface

The program demonstrates that only a closing function of the window

#include <Windows.h> //处理一些视觉特效,例如窗口,控件,枚举,样式

//在创建一个应用程序之前,必须先声明一个窗口过程的原型才能在窗口结构中使用它
LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam);

//WINAPI或stdcall意味着栈的清理工作由被调用函数来完成
//hThis是应用程序当前实例的句柄;hPrev是应用程序上一个实例的句柄;
//szCmdLine是应用程序的命令行,包括该程序的名称;iCmdShow控制如何显示窗口
int WINAPI WinMain(HINSTANCE hThis, HINSTANCE hPrev, LPSTR szCmdLine, int iCmdShow)
{
    UNREFERENCED_PARAMETER(hPrev); //告诉编译器不能使用某些参数,方便编译器进行一些额外的优化
    UNREFERENCED_PARAMETER(szCmdLine);

    WNDCLASSEX wndEx = { 0 }; //实例化窗口结构
    wndEx.cbClsExtra = 0; //实例化窗口类后分配的额外字节数
    wndEx.cbSize = sizeof(wndEx); //窗口结构的大小(字节为单位)
    wndEx.cbWndExtra = 0; //实例化窗口实例后分配的额外字节数
    wndEx.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1); //窗口类背景画刷的句柄
    wndEx.hCursor = LoadCursor(NULL, IDC_ARROW); //窗口类光标的句柄
    wndEx.hIcon = LoadIcon(NULL, IDI_APPLICATION); //窗口类图标的句柄
    wndEx.hIconSm = LoadIcon(NULL, IDI_APPLICATION); //窗口类图标的句柄
    wndEx.hInstance = hThis; //窗口过程的实例句柄
    wndEx.lpfnWndProc = WndProc; //指向窗口过程的指针
    wndEx.lpszClassName = TEXT("GUIProject"); //指向以空字符结尾的字符串或原子的指针
    wndEx.lpszMenuName = NULL; //指向以空字符结尾的字符串的指针,该字符串指定了窗口类菜单的资源名
    wndEx.style = CS_HREDRAW | CS_VREDRAW;

    if (!RegisterClassEx(&wndEx))
    {
        return -1;
    }

    HWND hWnd = CreateWindow( wndEx.lpszClassName, TEXT("GUI Project"), WS_OVERLAPPEDWINDOW,
                              200, 200, 400, 300, HWND_DESKTOP, NULL, hThis, 0);
    if (!hWnd)
    {
        return -1;
    }

    UpdateWindow(hWnd);

    ShowWindow(hWnd, iCmdShow); //设置指定窗口的显示状态
    MSG msg = { 0 }; //显示窗口消息

    while (GetMessage(&msg, NULL, NULL, NULL))
    {
        TranslateMessage(&msg); //把虚拟键消息翻译成字符消息
        DispatchMessage(&msg); //分发一条消息给窗口过程
    }

    DestroyWindow(hWnd);
    UnregisterClass(wndEx.lpszClassName, hThis); //注销窗口类,释放该类占用的内存
    return (int)msg.wParam; //从应用程序消息队列中返回一个成功推出代码或最后一个消息代码
}

//hWnd表示窗口标识,uMsg窗口消息代码(无符号整数),wParam和lParam传递应用程序定义的数据(64位长整型数)
//函数返回64位有符号长整型
LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
    switch (uMsg)
    {
    case WM_CLOSE:
    {
        PostQuitMessage(0); //释放系统资源,并安全关闭该应用程序
        break;
    }
    default:
    {
        //处理应用程序未处理的窗口信息,函数确保每个消息都被处理
        return DefWindowProc(hWnd, uMsg, wParam, lParam); //默认窗口过程
    }
    }
    return 0;
}

The following error:

严重性 代码  说明  项目  文件  行   禁止显示状态
警告  C28251  “WinMain”的批注不一致: 此实例包含 无批注。请参见 c:\program files (x86)\windows kits\10\include\10.0.18362.0\um\winbase.h(933)。   GUIProject  C:\USERS\CDQ\SOURCE\REPOS\GUIPROJECT\GUIPROJECT\MAIN.CPP    6   

The reason is to create a win32 console project rather than the project, the solution:

配置属性-->链接器-->系统-->子系统-->窗口，之后点击确定。

Reference from: https://bbs.csdn.net/topics/392512424?list=63174050

Second, explain the process model

Traditional operating system must provide a way to create a process and termination process, the following list four major events triggered creation process:

1. system initialization;
2. Running process execution system to create a process of calling;
3. Create a new user requirements process;
4. Start the batch job.

Create a process to open Windows Journal:

#include <iostream>
#include<windows.h>
int main()
{
    std::cout << "Hello World!\n";

    STARTUPINFO startupinfo = { 0 };
    PROCESS_INFORMATION processInfomation = {0};
        //CreateProcess函数用于创建一个新进程和其主线程。
    BOOL bSucess = CreateProcess(TEXT("C:\\windows\\notepad.exe"), NULL, NULL, NULL, FALSE, NULL, NULL, NULL, &startupinfo, &processInfomation);
    if (bSucess)
    {
        std::cout << "Process started." << std::endl
            << "Process ID:\t" << processInfomation.dwProcessId << std::endl;
    }
    else
    {
        std::cout << "Cannont create process!" << std::endl
            << "Error code:\t" << GetLastError() << std::endl;
    }
    return system("pause");
}

Better way to terminate the process is to call ExtiProcess function.

Third, the process status

Run: This process is using CPU;
ready: The process can run, but no CPU available, other processes are still waiting in line to give up the right to use the CPU;
blocking: in front of some external event occurs, the process can not run.

#include <iostream>
#include<windows.h>
//winternl包含了Windows内部函数大部分原型和数据类型
#include<winternl.h>

using std::cout;
using std::endl;

typedef NTSTATUS(WINAPI* QUERYINFORMATIONPROCESS)(
    HANDLE processHandle,
    PROCESSINFOCLASS processInformationClass,
    PVOID processInformation,
    ULONG processInformationLength,
    PULONG returnLength);

int main()
{
    std::cout << "Hello World!\n";

    STARTUPINFO startupinfo = { 0 };
    PROCESS_INFORMATION processInfomation = { 0 };

    BOOL bSuccess = CreateProcess(TEXT("C:\\windows\\notepad.exe"), NULL, NULL, NULL,
        FALSE, NULL, NULL, NULL, &startupinfo, &processInfomation);
    if (bSuccess)
    {
        std::cout << "Process started." << std::endl
            << "Process ID:\t" << processInfomation.dwProcessId << std::endl;

        PROCESS_BASIC_INFORMATION pbi;
        ULONG ulength = 0;

        HMODULE hDll = LoadLibrary(TEXT("C:\\windows\\System32\\ntdll.dll"));

        if (hDll)
        {
            QUERYINFORMATIONPROCESS QueryInformationProcess = (QUERYINFORMATIONPROCESS)GetProcAddress(hDll, "NtQueryInformationProcess");
            if (QueryInformationProcess)
            {
                NTSTATUS ntStatus = QueryInformationProcess(processInfomation.hProcess, PROCESSINFOCLASS::ProcessBasicInformation, &pbi, sizeof(pbi), &ulength);
                if (NT_SUCCESS(ntStatus))
                {
                    cout << "Process ID (from PCB):\t" << pbi.UniqueProcessId << endl;
                }
                else
                {
                    cout << "Cannot open PCB!" << endl
                        << "Error code:\t" << GetLastError() << endl;
                }
            }
            else
            {
                cout << "Cannot get NTQueryInformationProcess function!" << endl
                    << "Error code:\t" << GetLastError() << endl;
            }
            FreeLibrary(hDll);
        }
        else
        {
            cout << "Cannnot load ntdll.dll" << endl
                << "Error code:\t" << GetLastError() << endl;
        }
    }
    else
    {
        std::cout << "Cannont create process!" << std::endl
            << "Error code:\t" << GetLastError() << std::endl;
    }
    //CloseHandle(processInfomation.hProcess);
    //CloseHandle(processInfomation.hThread);
    return 0;
}

Hello World!
Process started.
Process ID:     11492
Process ID (from PCB):  11492