TThread mit Queue und Events

[Kas Ob.]

Zitat von jaenicke:

Zitat von Mavarik:

Doch genau das was er soll... Warten bis etwas neues in der Queue ist. (Oder Terminate)

Aber wer soll das Event auslösen, wenn ich z.B. einen Server pollen möchte, ob er neue Daten hat? Aber eben mit etwas Wartezeit dazwischen.

I don't recall a single Windows IO operation that doesn't support both blocking and non-blocking, synchronous or asynchronous, they all fall in one way or other under overlapped, and they all have the possibility to attach an event to automatically triggered, as for the same example like a server then either
1) block on "recv" and skip the event altogether or
2) block on "select" to get the state of the socket and have the exact moment of/for receiving data, or
3) use WSAEventSelect and WSAAsyncSelect , these are powerful to combine with other complex or non-complex operation, events here become central notification for one or more threads.
4) IOCP and don't even wait manually, get the operation and process the data in place within the thread knowing there is other threads allowed to process other client...
5) ..
6) ..
there is many approaches and that only for handling sockets on server or client side, same goes for files ReadFile and ReadFileEx, they have differences and can combined in many different ways, if you prefer events then overlapped with supplied event is the way to go, work like charm with com and legacy communication ports, allowing you to utilize the maximum throughput being writing files to disk or sending data to hardware wire or a driver ...

The overlapped design and operation are powerful and efficient, the core of overlapped mechanism is low level kernel triggered events.

Zitat von jaenicke:

Es gibt auch andere Konstellationen als dass ein Thread zur Beschleunigung durch Parallelisierung dienen soll oder auf konkret abfragbare Events wartet.

Of course there is, there is always such needed design where time interval is needed at the exact point, in other words, time is essential for non performed operation or non triggered event, may be a timer, may be we want to control the time out for a socket, short one and dont want to depend on socket provider timeout..etc ,
other than that i see polling as waste of time and CPU cycle as as Mavarik, for fast and lazy or limited usage then yes, poll then execute then sleep for short time, but with servers with many clients and many threads, this is a waste.