[Translted]Linux FAQs with Answers--How to catch and handle a signal in Perl

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zhengsihua 2014-09-27 11:10:41 +08:00
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Linux FAQs with Answers--How to catch and handle a signal in Perl
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> **Question**: I need to handle an interrupt signal by using a custom signal handler in Perl. In general, how can I catch and handle various signals (e.g., INT, TERM) in a Perl program?
As an asynchronous notification mechanism in the POSIX standard, a signal is sent by an operating system to a process to notify it of a certain event. When a signal is generated, the target process's execution is interrupted by an operating system, and the signal is delivered to the process's signal handler routine. One can define and register a custom signal handler or rely on the default signal handler.
In Perl, signals can be caught and handled by using a global %SIG hash variable. This %SIG hash variable is keyed by signal numbers, and contains references to corresponding signal handlers. Therefore, if you want to define a custom signal handler for a particular signal, you can simply update the hash value of %SIG for the signal.
Here is a code snippet to handle interrupt (INT) and termination (TERM) signals using a custom signal handler.
$SIG{INT} = \&signal_handler;
$SIG{TERM} = \&signal_handler;
sub signal_handler {
print "This is a custom signal handler\n";
die "Caught a signal $!";
}
![](https://farm4.staticflickr.com/3910/15141131060_f7958f20fb.jpg)
Other valid hash values for %SIG are 'IGNORE' and 'DEFAULT'. When an assigned hash value is 'IGNORE' (e.g., $SIG{CHLD}='IGNORE'), the corresponding signal will be ignored. Assigning 'DEFAULT' hash value (e.g., $SIG{HUP}='DEFAULT') means that we will be using a default signal handler.
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Linux 有问必答-- 如何在Perl中捕捉并处理信号
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> **提问**: 我需要通过使用Perl的自定义信号处理程序来处理一个中断信号。在一般情况下我怎么在Perl程序中捕获并处理各种信号如INTTERM
作为POSIX标准的异步通知机制信号由操作系统发送给进程某个事件来通知它。当产生信号时目标程序的执行是通过操作系统中断并且该信号被发送到处理该信号的处理程序。任何人可以定义和注册自定义信号处理程序或依赖于默认的信号处理程序。
在Perl中信号可以被捕获并被一个全局的%SIG哈希变量处理。这个%SIG哈希变量被信号号锁定并包含对相应的信号处理程序。因此如果你想为特定的信号定义自定义信号处理程序你可以直接更新%SIG的信号的哈希值。
下面是一个代码段来处理使用自定义信号处理程序中断INT和终止TERM的信号。
$SIG{INT} = \&signal_handler;
$SIG{TERM} = \&signal_handler;
sub signal_handler {
print "This is a custom signal handler\n";
die "Caught a signal $!";
}
![](https://farm4.staticflickr.com/3910/15141131060_f7958f20fb.jpg)
%SIG其他有效的哈希值有'IGNORE'和'DEFAULT'。当所分配的哈希值是'IGNORE'(例如,$SIG{CHLD}='IGNORE')时,相应的信号将被忽略。分配'DEFAULT'的哈希值(例如,$SIG{HUP}='DEFAULT'),意味着我们将使用一个默认的信号处理程序。
--------------------------------------------------------------------------------
via: http://ask.xmodulo.com/catch-handle-interrupt-signal-perl.html
译者:[geekpi](https://github.com/geekpi)
校对:[校对者ID](https://github.com/校对者ID)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译,[Linux中国](http://linux.cn/) 荣誉推出