Hi

I have to convert an MFC program to Linux.

In part of it a routine called by an interrupt sets an event, SetEvent().
A separate thread is waiting for that event to be set using WaitForSingleObject() function, before it can carry on.

I cannot find any reference to events in Linux so how would I do this.

Thanks
David

AFAIK there is no WaitForSingleObject equivalent in Linux
(I had to do with this in a software port a while ago, don't recall how I solved the problem, probably coded a solution
myself).

I haven't done anything with events since I programmed a mac, but I would suspect that events are handled by the gui toolkit you are using, like X11, GTK, or QT etc.

I am not using a gui tool kit.
The code is for a DLL (shared library) it does not need a gui.

David

linux isn't event-driven so there's no equivalent.
maybe you could use signals?
send a signal to the process from another?

These "events" are not GUI events. Way back in the old days the VMS operating system used the concept of events like a mutex/semaphore. You could wait() (unix: select()) on a list of events for any or all to complete. event resources were usually associated with device channels (unix: file descriptors). Instead of the contrived functionality of select() which had to be shared by everyone in the process, event were asynchronous and independent so that your library code didn't have to share a select loop with everyone else. Changes to an Event structure could trigger an AST (Asynchronous System Trap), basically a callback directly to your routine. It was extremely cool.

So why am I talking about VMS? Dave Cutler, one ot the main VMS kernel architects for Digital Electronics, left Digital in the late 1990's and went to work for Microsoft as the cheif architect for Windows NT. Windows NT is basically the next generation VMS. In fact, if you take the acronym "VMS" and add 1 to each letter you get "WNT". WinNT went on to become Win2K and WinXP. It has many other originally VMS concepts in it like IRPs (I/O Request Packets) and channels. Before WinNT, Windows was a joke of an OS, little more than a graphical toolkit on top of DOS. Microsoft needed outside help to build a real OS.

Anyways, it is unfortunate that these WinNT system Events have the same name as GUI events. Unix is not generally sophisticated enough to handle these concepts in a general purpose way. How you want to emulate Events depends on your scheduling needs. Your best best is to use pthreads (POSIX threads). These threads have several mechanisms for communicating between themselves, including mutexes (mutices?). pthread_cond_wait() is probably what you are looking for. Try doing a google search on "pthread communication".

Sorry to be long winded.

Thanks for the reply.

I am using pthreads already and will investigate it futher.
I am also looking at signals, as a previous message suggested.

I have been writing Windows programs since v3.0 but only started on Linux 2 months ago. There is alot to learn about the differences. It has been very interesting if at times frustrating, trying to match functions I have used for along time with there equivalent in Linux, and not always finding them.

Spooky about VMS/WNT reminds me of IBM/HAL.

David

It wasn't long-winded bm17, it was very interesting.
After all we log in here to try and help people and learn
something too.

It's a shame this fellow went to help the dark side tho'.

Imagine if his talents were used for good instead of evil.





billy

David, you might also have a look at wxWindows. Yes, it's a GUI toolkit, but also, IIRC it's very much like MFC. Perhaps you can make use of just the non-gui portion that you require. (?)