如何暂停正在运行的四个线程?
如何暂停正在运行的四个线程?
A = AfxBeginThread(ThreadFunc1,this);
B = AfxBeginThread(ThreadFunc2,this);
C = AfxBeginThread(ThreadFunc3,this);
D = AfxBeginThread(ThreadFunc4,this);
[解决办法]
DWORD SuspendThread( HANDLE hThread);
[解决办法]
不要使用SuspendThread!!!
1. 容易造成死锁。例如:线程A运行new操作符分配内存,多线程环境的new操作是要加锁的,如果正在已经加锁但还没有解锁的情况下线程A被Suspend了,那么进程内的其它线程只要一调用new操作符则必死无疑,死锁!!
MSDN中对SuspendThread的Remark:
This function is primarily designed for use by debuggers. It is not intended to be used for thread synchronization. Calling SuspendThread on a thread that owns a synchronization object, such as a mutex or critical section, can lead to a deadlock if the calling thread tries to obtain a synchronization object owned by a suspended thread. To avoid this situation, a thread within an application that is not a debugger should signal the other thread to suspend itself. The target thread must be designed to watch for this signal and respond appropriately.
2. SuspendThread之类的API都是针对User Mode的,当线程运行在Kernel Mode时,这些操作都是不起作用的。例如线程A正在调用WaitForSingleObject函数等待某个内核对象时,调用SuspendThread(A)是不起作用的。