我正在尝试获取线程的ID以存储在线程列表中。
为此,我将启动一个线程,该线程带有指向将存储线程 ID 的long
的指针。线程 ID 应在线程函数执行后立即存储。存储 ID 后,启动函数应该能够继续。
此代码似乎仅在调试模式下工作,但在发布模式下挂起。我正在使用Visual C++ 2008 Express。
我需要代码在Windows XP上运行,所以不幸的是我不能简单地使用GetThreadId
因为它仅在Windows Server 2003及更高版本上受支持。
thread_wrapper* spawn_thread(void *entryPoint, void *params)
{
thread_wrapper *newThread = calloc(1, sizeof(thread_wrapper));
_beginthread(spawned_thread_wrapper_func, 0, &newThread->_win32ThreadID);
while (newThread->_win32ThreadID == 0) ; // Hangs here in Release mode
... // Safely add thread to list using critical section
return newThread;
}
void spawned_thread_wrapper_func(void *params)
{
long *outThreadIDPtr = (long *)params;
*outThreadIDPtr = GetCurrentThreadId();
// spawn_thread function should now be able to add thread to list
// but still hangs on while waiting loop in Release mode.
// Works fine in Debug mode.
...
}
这里出了什么问题?
如果您希望该成员变量中的当前线程 id,这是使用 _beginthreadex()
的一种方法。该 api 使您可以更好地控制线程创建过程,以及用于检测线程终止(如果需要)的可等待句柄。请注意,线程进程的原型和下面的实现更改很重要。
thread_wrapper* spawn_thread(void *entryPoint, void *params)
{
thread_wrapper *newThread = calloc(1, sizeof(thread_wrapper));
// hThread is an OS thread handle you can wait on with
// wait functions like WaitForSingleObject.
HANDLE hThread = (HANDLE)_beginthreadex(NULL, 0,
spawned_thread_wrapper_func, newThread,
CREATE_SUSPENDED, &newThread->_win32ThreadID);
// TODO: add new thread (which is created, but not started yet)
// to your list.
// now resume the thread.
ResumeThread(hThread);
// if you don't need this any longer, close it, otherwise save it
// somewhere else (such as *before* the resume above, you can save
// it as a member of your thread_wrapper). No matter what, you have
// to close it eventually
// CloseHandle(hThread);
return newThread;
}
// note return value difference when using _beginthreadex.
unsigned int _stdcall spawned_thread_wrapper_func(void *params)
{
thread_wrapper* p = params; // note: with MS you may have to cast this.
// spawn_thread function should now be able to add thread to list
// but still hangs on while waiting loop in Release mode.
// Works fine in Debug mode.
...
}