Volker Stolz wrote:> In local.glasgow-haskell-users, you wrote:
I'm trying to get HTk to work on FreeBSD (actually FreeBSD running inside a VMware virtual machine, but I don't think that should make any difference). How HTk works is it creates a couple of pipes (readIn,writeIn) <- Posix.createPipe (readOut,writeOut) <- Posix.createPipe The problem I am getting with FreeBSD is that fdRead sometimes reports EOF, even though threadWaitRead has just reported the presence of data. (And no, I don't think we have a race condition here, the relevant bit of code is in an exclusive lock.) If I tell it to ignore the EOF and try to read again and again it just throws it into an endless loop, seemingly.
Can you cut this down to a simple program, maybe executing /bin/echo instead of 'wish'? Notice that the FAQ doesn't apply here as the FAQ talks about FIFO createt by mkfifo (which exist in the file system), while you talk about pipes.
I'll try to think of something, but I'd be glad if you already had a usable program to reproduce this error.
I think this one is going to remain unsolved. I have fixed the problem, by reimplementing the relevant code in a different way (actually resurrecting an old implementation, with a vital fix) and now it works. However the cause of the problem I reported is a mystery to me, and producing a simple test case does not look very easy. Thanks for your help, George