لطفا منتظر باشید ...
 |  |
16.22. Turning Signals into Fatal Errors
16.22.1. Problem
END blocks aren't run when your
program dies from an uncaught signal. Your program gets such signals,
and you'd like your END blocks to have a chance to clean up.
16.22.2. Solution
Use the sigtrap pragma:use sigtrap qw(die untrapped normal-signals);
16.22.3. Discussion
Untrapped signals cause your program to die without running END
blocks. Although you could manually install signal handlers that call
die, this becomes tedious for a lot of signals:$SIG{INT} = $SIG{HUP} = $SIG{PIPE} = $SIG{TERM} = sub { die };
The sigtrap pragma provides a convenient shorthand
for installing such handlers:use sigtrap qw(die untrapped normal-signals);
The die import tells sigtrap to
call die (you can also import
stack-trace to install handlers that trigger stack
traces). The untrapped import tells
sigtrap to install handlers only for signals that
don't already have them, so if you handle SIGPIPE
yourself, sigtrap won't replace your handler.normal-signals is one of several imports that
specify predefined lists of useful signals to trap. The signal lists
are given in Table 16-2.
Table 16-2. Signal lists
List | Signals |
|---|---|
normal-signals | HUP, INT, PIPE, TERM |
error-signals | ABRT, BUS, EMT, FPE, ILL, QUIT, SEGV, SYS, TRAP |
old-interface-signals | ABRT, BUS, EMT, FPE, ILL, PIPE, QUIT, SEGV, SYS, TERM, TRAP |
You can even combine different handler types in one import list. Here
we use untrapped to specify only the normal
signals for which there is not already a handler installed, then use
any to revert to sigtrap's
default behavior of installing handlers for all signals in the named
list:use sigtrap qw(
die untrapped normal-signals
stack-trace any error-signals
);
16.22.4. See Also
Recipe 12.7; the documentation for the
standard module sigtrap; Recipe 16.15
|  | |
| 16.21. Timing Out an Operation |  | 16.23. Program: sigrand |
Copyright © 2003 O'Reilly & Associates. All rights reserved.
