Signals

[carroll at s.cs.uiuc.edu]

/* Written  8:20 pm  Oct 23, 1988 by pjh at mccc.UUCP in s.cs.uiuc.edu:comp.unix.questions */
/* ---------- "Signals" ---------- */

> 1) What is signal 0?
It is a 'psuedo' signal, used by Bourne Shell and Korn Shell to mean 'the shell
is exiting normally'. Although you can set traps on it, they are caught by
mechanisms other than normal signal handling.

> 2) What signal does ^d (the logout key) generate?
As above, it generates the 'signal' 0. This has no meaning except for traps
set on 0. Since you refered to it as the 'logout' key (and not the end-of-file
key), I assume that you were asking about how it interacts with a shell.
For a normal program, it doesn't generate any signal.

Alan M. Carroll          "How many danger signs did you ignore?
carroll at s.cs.uiuc.edu     How many times had you heard it all before?" - AP&EW
CS Grad / U of Ill @ Urbana    ...{ucbvax,pur-ee,convex}!s.cs.uiuc.edu!carroll