【多线程】学习2

if (system("notepad.exe readme.txt") == -1)
{
    switch(errno)
    {
        ...//错误处理代码
    }
}

//_beginthreadex源码整理By MoreWindows( http://blog.csdn.net/MoreWindows )
_MCRTIMP uintptr_t __cdecl _beginthreadex(
    void *security,
    unsigned stacksize,
    unsigned (__CLR_OR_STD_CALL * initialcode) (void *),
    void * argument,
    unsigned createflag,
    unsigned *thrdaddr
)
{
    _ptiddata ptd;          //pointer to per-thread data 见注1
    uintptr_t thdl;         //thread handle 线程句柄
    unsigned long err = 0L; //Return from GetLastError()
    unsigned dummyid;    //dummy returned thread ID 线程ID号
    
    // validation section 检查initialcode是否为NULL
    _VALIDATE_RETURN(initialcode != NULL, EINVAL, 0);

    //Initialize FlsGetValue function pointer
    __set_flsgetvalue();
    
    //Allocate and initialize a per-thread data structure for the to-be-created thread.
    //相当于new一个_tiddata结构，并赋给_ptiddata指针。
    if ( (ptd = (_ptiddata)_calloc_crt(1, sizeof(struct _tiddata))) == NULL )
        goto error_return;

    // Initialize the per-thread data
    //初始化线程的_tiddata块即CRT数据区域 见注2
    _initptd(ptd, _getptd()->ptlocinfo);
    
    //设置_tiddata结构中的其它数据，这样这块_tiddata块就与线程联系在一起了。
    ptd->_initaddr = (void *) initialcode; //线程函数地址
    ptd->_initarg = argument;              //传入的线程参数
    ptd->_thandle = (uintptr_t)(-1);
    
#if defined (_M_CEE) || defined (MRTDLL)
    if(!_getdomain(&(ptd->__initDomain))) //见注3
    {
        goto error_return;
    }
#endif  // defined (_M_CEE) || defined (MRTDLL)
    
    // Make sure non-NULL thrdaddr is passed to CreateThread
    if ( thrdaddr == NULL )//判断是否需要返回线程ID号
        thrdaddr = &dummyid;

    // Create the new thread using the parameters supplied by the caller.
    //_beginthreadex()最终还是会调用CreateThread()来向系统申请创建线程
    if ( (thdl = (uintptr_t)CreateThread(
                    (LPSECURITY_ATTRIBUTES)security,
                    stacksize,
                    _threadstartex,
                    (LPVOID)ptd,
                    createflag,
                    (LPDWORD)thrdaddr))
        == (uintptr_t)0 )
    {
        err = GetLastError();
        goto error_return;
    }

    //Good return
    return(thdl); //线程创建成功,返回新线程的句柄.
    
    //Error return
error_return:
    //Either ptd is NULL, or it points to the no-longer-necessary block
    //calloc-ed for the _tiddata struct which should now be freed up.
    //回收由_calloc_crt()申请的_tiddata块
    _free_crt(ptd);
    // Map the error, if necessary.
    // Note: this routine returns 0 for failure, just like the Win32
    // API CreateThread, but _beginthread() returns -1 for failure.
    //校正错误代号(可以调用GetLastError()得到错误代号)
    if ( err != 0L )
        _dosmaperr(err);
    return( (uintptr_t)0 ); //返回值为NULL的效句柄
}

//创建多子个线程实例
#include <stdio.h>
#include <process.h>
#include <windows.h>
//子线程函数
unsigned int __stdcall ThreadFun(PVOID pM)
{
    printf("线程ID号为%4d的子线程说：Hello World\n", GetCurrentThreadId());
    return 0;
}
//主函数，所谓主函数其实就是主线程执行的函数。
int main()
{
    printf("     创建多个子线程实例 \n");
    printf(" -- by MoreWindows( http://blog.csdn.net/MoreWindows ) --\n\n");
    
    const int THREAD_NUM = 5;
    HANDLE handle[THREAD_NUM];
    for (int i = 0; i < THREAD_NUM; i++)
        handle[i] = (HANDLE)_beginthreadex(NULL, 0, ThreadFun, NULL, 0, NULL);
    WaitForMultipleObjects(THREAD_NUM, handle, TRUE, INFINITE);
    return 0;
}

//子线程报数
#include <stdio.h>
#include <process.h>
#include <windows.h>
int g_nCount;
//子线程函数
unsigned int __stdcall ThreadFun(PVOID pM)
{
    g_nCount++;
    printf("线程ID号为%4d的子线程报数%d\n", GetCurrentThreadId(), g_nCount);
    return 0;
}
//主函数，所谓主函数其实就是主线程执行的函数。
int main()
{
    printf("     子线程报数 \n");
    printf(" -- by MoreWindows( http://blog.csdn.net/MoreWindows ) --\n\n");
    
    const int THREAD_NUM = 10;
    HANDLE handle[THREAD_NUM];

    g_nCount = 0;
    for (int i = 0; i < THREAD_NUM; i++)
        handle[i] = (HANDLE)_beginthreadex(NULL, 0, ThreadFun, NULL, 0, NULL);
    WaitForMultipleObjects(THREAD_NUM, handle, TRUE, INFINITE);
    return 0;
}