| |||
A process that responds to signals
Interprocess Communication example from a Well House Consultants training course
More on Interprocess Communication [link]
Source code: nonfat Module: P223
# A process that responds to signals
# Just note signals as they're received sub bob{ $flagvar = 1; } sub tom{ $tomvar = 1; } # Set up ho we're to react when we get a signal $SIG{INT} = \&bob; # Control C (Careful - how do you really kill?) $SIG{USR1} = \&tom; # User Controlled PID $flagvar = $tomvar = 0; # Log our process ID into a file so that other processes # know how to communicate with us! print "My Process ID is $$\n"; open(FH,">$0.pid") and print FH "$$\n" and close FH; # Action loop while (1) { print "hello\n"; sleep 2; $counter ++; last if ($counter > 20); # If any signals were received during the last cycle # act on them at this point if ($flagvar) { print "givem a report after $counter times\n"; $flagvar = 0; } if ($tomvar) { print "A FULL report and other action\n"; $tomvar = 0; } } __END__ Sample Output: wizard:csr2 graham$ perl nonfat My Process ID is 211 hello hello hello A FULL report and other action hello hello hello hello A FULL report and other action hello hello ^Cgivem a report after 9 times hello ^Cgivem a report after 10 times hello ^Cgivem a report after 11 times hello hello hello hello hello hello hello hello hello hello wizard:csr2 graham$ Learn about this subject
This module and example are covered on our public Perl Extra course. If you have a group of
three or more trainees who need to learn the subject, we can also arrange a
private or on site course for you.
Books covering this topic
Yes. We have over 700 books in our library. Books
covering Perl are listed here and when you've selected a
relevant book we'll link you on to Amazon to order.
Other Examples
This example comes from our "Interprocess Communication" training module. You'll find a description of the topic and some
other closely related examples on the "Interprocess Communication" module index page.
Full description of the source code
You can learn more about this example on the training courses listed on this page,
on which you'll be given a full set of training notes.
Many other training modules are available for download (for limited use) from our download centre under an Open Training Notes License. Other resources
• Our Solutions centre provides a number of longer technical articles.
• Our Opentalk forum archive provides a question and answer centre. • The Horse's mouth provides a daily tip or thought. • Further resources are available via the resources centre. • All of these resources can be searched through through our search engine • And there's a global index here. Purpose of this website
This is a sample program, class demonstration or answer from a
training course. It's main purpose
is to provide an after-course service to customers who have attended our
public private or
on site courses, but the examples are made
generally available under conditions described below.
Web site author
Conditions of use
Past attendees on our training courses are welcome to use individual
examples in the course of their programming, but must check
the examples they use to ensure that they are suitable for their
job. Remember that some of our examples show you how not to do
things - check in your notes. Well House Consultants take no responsibility
for the suitability of these example programs to customer's needs.
This program is copyright Well House Consultants Ltd. You are forbidden from using it for running your own training courses without our prior written permission. See our page on courseware provision for more details. Any of our images within this code may NOT be reused on a public URL without our prior permission. For Bona Fide personal use, we will often grant you permission provided that you provide a link back. Commercial use on a website will incur a license fee for each image used - details on request. | |||
PH: 01144 1225 708225 • EMAIL: info@wellho.net • WEB: http://www.wellho.net • SKYPE: wellho PAGE: http://www.wellho.net/resources/ex.php • PAGE BUILT: Sun Oct 11 14:50:09 2020 • BUILD SYSTEM: JelliaJamb |