Original Post
Hello everyone,
I’m hoping someone can help me. This has nothing to do with game programming but still hoping someone can help me out. I have a lib file, which is a static library from a third party that allows me to communicate with their server without me having to worry about the TCP\IP commutation. I don’t have access to this code at all. I’m having a problem that I’m hoping someone can help me with. Ok, I have to create an instance of their class and pass in a callback function. Once I pass in the callback function it will send me a message when it has connected to the server or errors like a bad username or password. Well, here my problem. I don’t want to leave my function(in this example, MyLogin) until I have the status of the connection, either being connected to the server or bad username/password. The reason I’m having trouble is because when I pass in the callback function, the callback function is on the same thread as MyLogin, so when I do something like Sleep, WaitForMultipleObjects, the callback function never receives messages because I’m telling that thread to sleep. I was hoping there was a api like MsgWaitForMultipleObjects but to allow me to process the callback function events but there isn’t. Here is an example of what I’m talking about
HANDLE thisEvent[2];
MyCallBack(Message msg)
{
if(msg = thisEvent)
{
SetEvent(thisEvent[0]);
{
else
{
SetEvent(thisEvent[1]);
}
}
MyLogin()
{
thisEvent[0] = CreateEvent();
thisEvent[1] = CreateEvent();
MyClass *Example;
Example = new(MyCallBack);
Example ->Login("user", "pass");
::WaitForMultipleObjects(2, thisEvent, FALSE, INFINITE);
}
but like I said, once I call the function WaitForMultipleObjects, the callback function never gets called because they’re on the same thread. So I had another idea, have my main thread create the object, pass it to a worker thread and have it wait, like this
MyCallBack(Message msg)
{
if(msg = thisEvent)
{
SetEvent(thisEvent[0]);
{
else
{
SetEvent(thisEvent[1]);
}
}
DWORD WINAPI LoginThread(LPVOID lpObject)
{
MyCallBack *Object =( MyCallBack *)lpObject;
Object ->Login("user", "pass");
::WaitForMultipleObjects(2, thisEvent, FALSE, INFINITE);
}
MyLogin()
{
thisEvent[0] = CreateEvent();
thisEvent[1] = CreateEvent();
MyClass *Example;
Example = new(MyCallBack);
hThread = CreateThread(NULL, 0, LoginThread, (LPVOID)Example, 0,NULL)
WaitForSingleObject(1, hThread, INFINITE);
}
Once again, the callback never gets called because both threads are now sleeping. So I had another idea, have the worker thread not wait at all, like this
MyCallBack(Message msg)
{
if(msg = thisEvent)
{
SetEvent(thisEvent[0]);
{
else
{
SetEvent(thisEvent[1]);
}
}
DWORD WINAPI LoginThread(LPVOID lpObject)
{
MyCallBack *Object =( MyCallBack *)lpObject;
Object ->Login("user", "pass");
}
MyLogin()
{
thisEvent[0] = CreateEvent();
thisEvent[1] = CreateEvent();
MyClass *Example;
Example = new(MyCallBack);
hThread = CreateThread(NULL, 0, LoginThread, (LPVOID)Example , 0,NULL)
WaitForSingleObject(1, hThread, INFINITE);
}
but it crashes, and I think it crashes because the thread terminates before login completes or maybe because login is the one that is calling the callback function but before the callback is called, the thread is terminated so you are calling a callback function on a thread that no longer exist.. So if anyone can help me with this problem I would really be thankful. Once again, what I need to do is process the callback function events before leaving MyLogin….Thank you for everyones help
Michael
[edited by - bravescharm on June 12, 2002 1:54:37 PM]
[edited by - bravescharm on June 12, 2002 1:55:41 PM]