In the following example we can see the usage of alarm signal handler '$SIG{ALRM}' in Perl.
$SIG{ALRM} is used to execute definite lines of code on regular time intervals, in a program's normal course of execution. Here we shall display "Hello World" text after every 30 seconds.
Here the following Program name is 'test_alarm.pl'
#!/usr/bin/perl
## setup alarm signal handler to execute timely
our $alarm_interval = 30; # 30 secs
$SIG{ALRM} = sub {
print "Hello World\n";
alarm($alarm_interval);
};
alarm($alarm_interval);
### Infinite loop to test out running of alarm
while (1) {
}
Steps To Run The Program:
-------------------------
1) On the command prompt goto the directory where the program is created, type the following and hit enter.
perl test_alarm.pl
Output of the above program is either of the following lines:
Hello World
Hello World
Hello World
