Please forgive these questions I post to the list to which I know the answer. Or rather: *an* answer. I learn a lot from others' responses. Even if it's "my way is best after all" -- that's a valuable thing to know.
I have two separate J processes running (assume Linux / Darwin, though I'm keen on cross-platform solutions). They communicate by each writing a text file which is read by the other (keep-it-simple-stupid). Is there a neat, robust way of one process asking the other: "are you there?" or "are you still alive?" I'm au-fait with how the yellow-J works, all the solutions involving timer-driven duty-cycles, timeouts, and reading files written by the sister process, Or the files' timestamps, or permissions. But these all seem so clunky. I guess what I want is something that was so easy in the 1970s but is so awkward on today's machines: just reserve a pair of bits in absolute memory -- or a pair of pixels on the screen -- or some inessential system flags -- and play pat-a-cake with them. Once upon a time there was such a thing as "common memory". ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm