Worker线程使用消息循环

最新推荐文章于 2022-08-16 10:26:11 发布

原创最新推荐文章于 2022-08-16 10:26:11 发布 · 1.2k 阅读

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#win32 线程

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这个示例代码展示了如何在Win32环境中创建一个带有自己消息队列但没有窗口的worker线程。主线程通过PostThreadMessage发送WM_JOB_开头的消息，worker线程根据消息类型进行不同操作，如正向打印、反向打印和转换为小写等。

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/*
 * Worker.cpp
 *
 * Sample code for "Multithreading Applications in Win32"
 * This is from Chapter 14, Listing 14-3
 *
 * Demonstrate using worker threads that have
 * their own message queue but no window.
 */
 
#define WIN32_LEAN_AND_MEAN
#include <stdio.h>
#include <stdlib.h>
#include <windows.h>
#include <process.h>
#include <string.h>
#include "MtVerify.h"

unsigned WINAPI ThreadFunc(void* p);

HANDLE ghEvent;

#define WM_JOB_PRINT_AS_IS          WM_APP + 0x0001
#define WM_JOB_PRINT_REVERSE        WM_APP + 0x0002
#define WM_JOB_PRINT_LOWER          WM_APP + 0x0003
#define WM_LEIWEI					WM_APP + 0x0004
int main(VOID) 
{ 
    HANDLE hThread;
    unsigned tid;

    // Give the new thread something to talk
    // to us with.

	//创建手动事件

    ghEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
	unsigned CurrentId = GetCurrentThreadId();

	UNREFERENCED_PARAMETER(CurrentId);

    hThread = (HANDLE)_beginthreadex(NULL,
                      0,
                      ThreadFunc,
                      0,
                      0,
                      &tid );
    MTVERIFY(hThread);

    // This thread has to wait for the new thread
    // to init its globals and msg queue.
    WaitForSingleObject(ghEvent, INFINITE);//等待事件有信号

    // The only place in the book we get to use
    // the thread ID!
	//strdup 调用的是malloc所以需要free
    char *szText = strdup("Thank you for buying this book.\n");
    PostThreadMessage(tid, WM_JOB_PRINT_AS_IS, NULL, (LPARAM)szText);

    szText = strdup("Text is easier to read forward.\n");
    PostThreadMessage(tid, WM_JOB_PRINT_REVERSE, NULL, (LPARAM)szText);

    szText = strdup("\nLOWER CASE IS FOR WHISPERING.\n");
    PostThreadMessage(tid, WM_JOB_PRINT_LOWER, NULL, (LPARAM)szText);

	Sleep(4000);

	//给线程发消息，退出
	PostThreadMessage(tid,WM_QUIT,0,0);

    WaitForSingleObject(hThread, INFINITE);//等待线程退出，然后关闭句柄

    CloseHandle(hThread);

	system("pause");

    return 0;
}
 
VOID CALLBACK TimerFunc(
    HWND hwnd,  // handle of window for timer messages 
    UINT uMsg,  // WM_TIMER message
    UINT idEvent,   // timer identifier
    DWORD dwTime )  // current system time
{
	//取消编译器的警告，没有引用的变量
    UNREFERENCED_PARAMETER(hwnd);
    UNREFERENCED_PARAMETER(uMsg);
	printf("onTimer function\n");

  //  PostThreadMessage(GetCurrentThreadId(), WM_QUIT,0,0);
	unsigned id = GetCurrentThreadId();

	PostThreadMessage(id, WM_LEIWEI,0,0);
}
 
/*
 * Call a function to do something that terminates
 * the thread with ExitThread instead of returning.
 */
unsigned WINAPI ThreadFunc(LPVOID n)
{
    UNREFERENCED_PARAMETER(n);

    MSG msg;

    // This creates the message queue.
	//创建一个消息队列
    PeekMessage(&msg, NULL, 0, 0, PM_NOREMOVE);

	//设置事件有激活
    SetEvent(ghEvent);

    // We'll run for two seconds
    SetTimer(NULL, NULL, 500, (TIMERPROC)TimerFunc);

    while (GetMessage(&msg, NULL, 0, 0))
    {
        char *psz = (char *)msg.lParam;
        switch(msg.message)
        {
        case WM_JOB_PRINT_AS_IS:
            printf("%s", psz);
            free(psz);
            break;
        case WM_JOB_PRINT_REVERSE:
            printf("%s", strrev(psz));
            free(psz);
            break;
        case WM_JOB_PRINT_LOWER:
            printf("%s", _strlwr(psz));
            free(psz);
            break;
		case WM_LEIWEI:
			printf("timer:............\n");
			break;
        default:
			printf("message id=%0X\n",msg.message);
            DispatchMessage(&msg);
        }
    }

    return 0;
}