我正在尝试创建一个程序,通过给定的进程ID检测进程终止。但我不能给回调函数任何参数。我怎样才能实现这一目标?谢谢。
void CALLBACK WaitOrTimerCallback(
_In_ PVOID lpParameter,
_In_ BOOLEAN TimerOrWaitFired,
DWORD processID)
{
MessageBox(0, L"The process has exited.", L"INFO", MB_OK);
std::cout << processID << std::endl;
return;
}
int main()
{
DWORD dwProcessID = 1234;
HANDLE hProcHandle = OpenProcess(PROCESS_ALL_ACCESS, FALSE, dwProcessID);
HANDLE hNewHandle;
RegisterWaitForSingleObject(&hNewHandle, hProcHandle, WaitOrTimerCallback(?, ?, dwProcessID), NULL, INFINITE, WT_EXECUTEONLYONCE);
}
RegisterWaitForSingleObject()
有一个Context
参数,用于将用户定义的数据传递给回调。例如:
void CALLBACK WaitOrTimerCallback(
_In_ PVOID lpParameter,
_In_ BOOLEAN TimerOrWaitFired)
{
DWORD dwProcessID = reinterpret_cast<DWORD>(lpParameter);
MessageBox(0, L"The process has exited.", L"INFO", MB_OK);
std::cout << dwProcessID << std::endl;
}
int main()
{
DWORD dwProcessID = 1234;
HANDLE hProcHandle = OpenProcess(SYNCHRONIZE, FALSE, dwProcessID);
if (hProcHandle)
{
HANDLE hNewHandle;
if (RegisterWaitForSingleObject(&hNewHandle, hProcHandle, &WaitOrTimerCallback, reinterpret_cast<void*>(dwProcessID), INFINITE, WT_EXECUTEONLYONCE))
UnregisterWait(hNewHandle);
CloseHandle(hProcHandle);
}
return 0;
}
虽然,在这个特殊的例子中,当RegisterWaitForSingleObject()
足够时,使用带有INFINITE
超时的WaitForSingleObject()
是过度的:
int main()
{
DWORD dwProcessID = 1234;
HANDLE hProcHandle = OpenProcess(SYNCHRONIZE, FALSE, dwProcessID);
if (hProcHandle)
{
if (WaitForSingleObject(hProcHandle, INFINITE) == WAIT_OBJECT_0)
{
MessageBox(0, L"The process has exited.", L"INFO", MB_OK);
std::cout << dwProcessID << std::endl;
}
CloseHandle(hProcHandle);
}
return 0;
}
当您想要在后台异步等待对象时,应该使用RegisterWaitForSingleObject()
,同时继续执行其他操作。不要等待等待操作。操作系统将在发出对象信号时通知您。