Le 13/12/2020 à 03:15, Steve Litt a écrit : > On Fri, 11 Dec 2020 15:53:35 +0100 > Didier Kryn <k...@in2p3.fr> wrote: > > >> I don't make it an argument against xdm. Just cheating about your >> own arguments (~: > Didier, why didn't you make that suggestion to me 15 years ago? It's a > brilliant way to guarantee that if somebody logs out of X, they have no > logged in shell to make mischief with. > > I should have thought of that myself. 15 years ago :-). > Yes you should have. But this is something everybody forgets all the time. We all imagine a program invocation like a function call, in which the caller is suspended until the callee returns; but actually when the shell is suspended waiting the application to return, it intentionnally waits, but can easily stop waiting. The artefact is that we must add an '&' to tell it not to wait in the first place. This is a semantic sugar to make it behave by default "as if" it was a function call.
exec does not create a new process; instead it substitutes the new application to the current one (the shell). I had fun some years ago writing an application which opened an http connection to a server on standard input, read the http header, and then execed another application given in argument. -- Didier _______________________________________________ Dng mailing list Dng@lists.dyne.org https://mailinglists.dyne.org/cgi-bin/mailman/listinfo/dng
