Re: Async IO

Greg Alexander (galexand@sietch.bloomington.in.us)
Mon, 27 Jan 1997 20:36:25 -0500 (EST)


On Mon, 27 Jan 1997, Nathan Bryant wrote:

> On Sun, 26 Jan 1997, Greg Alexander wrote:
>
> > You only need to use one signal, then the signal handler will look at some
> > shared memory to see what the signal was for. And there's no really good
> > reason that i know of to not use SIGHUP, SIGCHLD, SIGIO, SIGPWR, etc.
>
> Using shared memory from signal handlers isn't easy. The pthreads
> synchronization routines can't be called from signal handlers, because
> they rely on signals to wake up a task that's blocked on a mutex or
> condition.

aren't you over-complexicating? All you need for threading is clone(2) and
mmap(2).

> Async I/O can be done on linux, but it can't be done portably until Linux
> gets better signal support.

mmap had darn better be portable. :) And you can do it with just fork.

Greg Alexander
http://www.cia-g.com/~sietch/