第7章 线程调度、优先级和亲缘性(2)

7.7 在实际上下文中谈CONTEXT结构

（1）线程CONTEXT记录线程的状态（如CPU各寄存器状态），以供下次调度时从停止处继续。

（2）CONTEXT的结构（要获得或设置时，必须在Context.ContextFlags设置相应的标志）

★CONTEXT_FULL标志 = CONTEXT_CONTROL | CONTEXT_INTEGER | CONTEXT_SEGMENTS

（3）获取和设置上下文

①先挂起线程和设置CONTEXT结构体相应的标志

②Get\SetThreadContext;

【ThreadContext程序】显示线程上下文的CPU寄存器状态

#include <windows.h>
#include <tchar.h>
#include <locale.h>

//线程函数
DWORD WINAPI ThreadProc(PVOID pvParam)
{
    HANDLE hEvent = (HANDLE)pvParam;
    WaitForSingleObject(hEvent, INFINITE);
    CloseHandle(hEvent);
    return 0;
}

int _tmain()
{
    _tsetlocale(LC_ALL, _T("chs"));

    HANDLE hEvent = CreateEvent(NULL, FALSE, FALSE, NULL);
    HANDLE hEventDup = NULL;
    DuplicateHandle(GetCurrentProcess(), hEvent,
                    GetCurrentProcess(), &hEventDup,
                    DUPLICATE_SAME_ACCESS,FALSE,0);

    HANDLE hThread = CreateThread(NULL, 0, ThreadProc, hEventDup,
                                  CREATE_SUSPENDED,NULL);
    ResumeThread(hThread);

    SuspendThread(hThread);
    CONTEXT ct = {0};
    ct.ContextFlags = CONTEXT_ALL;
    GetThreadContext(hThread, &ct);

    //显示CONTEXT的内容
    _tprintf(_T("CPU寄存器状态：\n"));
    _tprintf(_T("\tEAX=0x%08X,EBX=0x%08X\n"),ct.Eax,ct.Ebx);
    _tprintf(_T("\tECX=0x%08X,EDX=0x%08X\n"), ct.Ecx, ct.Edx);
    _tprintf(_T("\tESI=0x%08X,EDI=0x%08X\n"), ct.Esi, ct.Edi);
    _tprintf(_T("\tEIP=0x%08X,ESP=0x%08X\n"), ct.Eip, ct.Esp);
    _tprintf(_T("\tEBP=0x%08X,EFL=0x%08X\n"), ct.Ebp, ct.EFlags);

    ResumeThread(hThread);
    SetEvent(hEvent);

    CloseHandle(hEvent);
    CloseHandle(hThread);
    _tsystem(_T("PAUSE"));
    return 0;
}