第五章 作业

（1）作业是什么？

　　你可以把作业想象成一个进程的容器，作用是限制一组进程的属性。读懂下面的示例函数，就差不多理解了。

void StartRestrictedProcess（）
{
    bool bInJob =FALSE;   
    IsProcessInJob(GetCurrentProcess(),NULL,&bInJob);   
    if(bInJob)
    {
        Messagebox(TEXT("进程已经存在作业中"),TEXT(""),MB_OK|MB_ICONINFORMATION);
        return;
    }
    
    HANDLE hjob = CreateJobObject(NULL,TEXT("作业"));
    JOBOBJECT_BASIC_LIMIT_INFORMATION jobli ={ 0 };
    jobli.PriorityClass = IDLE_PRIORITYCLASS;//CPU 级别
    jobli.PerJobUserTimeLimit.QuadPart = 10000000;//进程每个时间不能超过1s
    jobli.LimitFlags = JOB_OBJECT_LIMIT_PRIORITY_CLASS | OB_OBJECT_LIMIT_JOB_TIME;
    
    SetInformationJobObject(hjob, JobObjectBasicLimitInformation,&jobli, sizeof(jobli));
   
    JOBOBJECT_BASIC_UI_RESTRICTIONS jobuir;
    jobuir.UIRestrictionsClass = JOB_OBJECT_UILIMIT_NONE; 
    jobuir.UIRestrictionsClass |= JOB_OBJECT_UILIMIT_EXITWINDOWS;  
    jobuir.UIRestrictionsClass |= JOB_OBJECT_UILIMIT_HANDLES; 

    SetInformationJobObject(hjob,JobObjectBasicUIRestrictions, &jobuir, sizeof(jobuir)); 
   
    STARTUPINFO si = { sizeof(si) };  
    PROCESS_INFORMATION pi;    
    CreateProcess(NULL, "CMD", NULL, NULL, FALSE, CREATE_SUSPENDED, NULL, NULL, &si, π); 
    AssignProcessToJobObject(hjob,pi.hProcess); 
    ResumeThread(pi.hThread);    
    CloseHandle(pi.hThread); 
   
    HANDLE h[2];    
    h[0] = pi.hProcess;    
    h[1] = hjob;    
    DWORD dw = WaitForMultipleObjects(2,h,FALSE,INFINITE); 
    
    switch( dw-WAIT_OBJECT_0 )
    {      
        case 0:         //线程被停止    
             break;     
        case 1:             
            break;          
    }
    CloseHandle(pi.hProcess);
    CloseHandle(hjob);
}