🚀 go-pugleaf

I write:

>     It's possible this belongs on one of the UNIX groups, but it
>touches on some NeXT stuff so I thought I'd try here first. I'm in
>the midst of doing an App that uses Allegro for some NLP stuff. I'm
>spawning a cl process and making its stdin one end of a pipe, and its
>stdout another end of a pipe like this:
>
>if((pid = fork()) == 0) {
>	fclose(stdin);
>	dup(cl_stdin);
>	fclose(stdout);
>	dup(cl_stdout);
>	execl(...);
>	}
>
>     Here's my problem. Common Lisp can respond to commands in its
>own sweet time. I don't want to sit around polling on the file
>descriptor all the time. This would hose the user interface. What
>I want to happen is this:
>
>     When the OS detects something to be read on the descriptor it
>wakes up a thread (or whatever) and the thread takes care of all my I/O.
>I think maybe the SIGIO signal sort of does this -- but it seems awefully
>crufty to me. (Not thread based at all, and who wants to poll ALL the
>possible descriptors.)
>

I got loads of great responses for this. Thanks! Just to save time and
bandwidth I figured I'd summarize.

Basically there are two facilities for doing this. The first is a vanilla
BSD routine called select(2). The second is a NeXTstep specific called
DPScallFD(). Alternatively there is a NeXTstep example called Subprocess
which does all this for you. Guess which I'll use :)

-Chris