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30 lines
2.1 KiB
Markdown
30 lines
2.1 KiB
Markdown
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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?
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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.
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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.
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Here is a code snippet to handle interrupt (INT) and termination (TERM) signals using a custom signal handler.
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$SIG{INT} = \&signal_handler;
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$SIG{TERM} = \&signal_handler;
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sub signal_handler {
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print "This is a custom signal handler\n";
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die "Caught a signal $!";
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}
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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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via: http://ask.xmodulo.com/catch-handle-interrupt-signal-perl.html
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译者：[译者ID](https://github.com/译者ID)
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校对：[校对者ID](https://github.com/校对者ID)
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本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](http://linux.cn/) 荣誉推出
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