NAME
signal - dynamically loadable signal handling for Tcl/Tk
SYNOPSIS
signal (add|delete|print|version) [options]
COMMANDS
add signo
proc [-async]
Adds a signal handler for signal signo through proc proc.
Signals can be provided by number, or the most common ones
are provided by name (e.g., SIGHUP). The proc is any Tcl
procedure, and it is evaluated when the signal comes in. It
will be provided no arguments.
Signal handlers have Posix semantics - they persist until reset.
If -async is used, the signal handler is created using Tcl_AsyncCreate(). Checks for the signal are very frequent (each evaluation) using this technique, but one doesn’t know quite where evaluation is or how to handle errors in this situation. The code will evaluate the provided procedure in the current interpreter if available, and in the interpreter which added the signal handler otherwise. At least until a better scheme is suggested.
The -async is especially useful to interrupt "runaway" procs, or to cause a quick exit; the default mechanism simply waits for another MainLoop cycle.
signal
delete signo
Restores handling of signal signo to the default (
SIG_DFL ).
signal
print
Prints the handling of all signals with handlers. Formatted
as
signal ----> procedure or as
signal !---> procedure
if the signal is handled asynchronously
signal print
signo
Prints the procedure for handling signal signo. Prints the
word UNHANDLED if no signal handler is active for
that signal.
signal
version
Returns the string representing the current version of the
package
AUTHOR
Michael Schwartz <mschwart [AT] nyx.net>. Tilman Kranz <tilde [AT] tk-sls.de> patched this for wider portability on Linux