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$SIG{WARN}的用法

已有 1483 次阅读| 2013-1-29 15:52 |个人分类:技术文章

Example:

#! /usr/bin/perl

use warnings;

use strict;

$SIG{__WARN__} = sub {

my $msg = shift;

print STDERR "$msg\n";

print "use warn handler\n";

};

chomp (my $filename = <>);

open (RFILE, $filename) || warn "cannot open $filename";

注意：$SIG{__WARN__} = sub{...}; 的大括号后面有分号。

No message is printed if there is a $SIG{__WARN__} handler installed. It is the handler's responsibility to deal with the message as it sees fit (like, for instance, converting it into a die). Most handlers must therefore arrange to actually display the warnings that they are not prepared to deal with, by calling warn again in the handler. Note that this is quite safe and will not produce an endless loop, since __WARN__ hooks are not called from inside one.