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<H2>HiPi::Interrupt::Handler</H2><p>This module provides access to interrupt handling and inter thread communication in your main thread.</p>
<p>The main interrupt module, <A HREF="interrupt_hipi_interrupt.htm">HiPi::Interrupt</A>, must be loaded at the beginning of your script. You may then either create your own class deriving from HiPi::Interrupt::Handler to handle interrupts or you can use an instance of the class directly providing one or more callback code references.</p>
<p>Working examples are provided in:</p>
<p>
<UL>
<li><A HREF="interrupt_example_derived.htm">Derived Class Example</A>
<li><A HREF="interrupt_example_callback.htm">Callback Example</A>
<li><A HREF="interrupt_example_mixed.htm">Mixed Handlers Example</A>
</UL>
</p>
<p>You choose to deal with notifications either by registering callbacks with an instance of HiPi::Interrupt::Handler or you may create your own class deriving from HiPi::Interrupt::Handler and override its methods.</p>
<h2>Constructor</h2>
<h3>my $handler = HiPi::Interrupt::Class->new();</h3>
<h2>Methods</h2>
<h3>$handler->add_pin($pin);<br>
$handler->add_pin($pinnumber, $pinclass);</h3>
<p>Method add_pin takes either a pin object inheriting from class HiPi::Pin or a GPIO pin number and a pinclass defining how the pin is managed ( <B>gpio</B> for sysfs HiPi::Device::GPIO pins, <B>bcmd</B> for HiPi::BCM2835 pins and <B>wire</B> for HiPi::Wiring pins.</p>
<p>The pin will be polled for interrupts. It is assumed that all of the necessary settings will have been applied to the pin prior to a call to $handler->add_pin.</p>
<h3>$handler->remove_pin($pin);<br>
$handler->remove_pin($pinnumber);</h3>
<p>Removes the pin from interrupt polling.</p>
<h3>$handler->stop;</h3>
<p>Stops and exits the $handler poll loop. Call this to close your application.</p>
<h3>$handler->poll;</h3>
<p>Call this to begin polling for pin interrupts. The method will not return until your code calls $handler->stop. After calling $handler->poll, your code execution continues in the main application thread by calls to methods in your custon HiPi::Interrupt::Handler class or through callbacks you have registered with your $handler instance.</p>
<h3>$handler->register_callback( $cbname, $coderef );</h3>
<p>Rather than create your own class derived from HiPi::Interrupt::Handler, you can create an instance of HiPi::Interrupt::Handler directly and register callback subroutines to receive notifications. The code reference specified in $coderef will be called with the same parameters described in the Notification Methods below for the relevant $cbname. Possible values for $cbname are <br><I>start, continue, interrupt, error, add, remove, stop</I>.</p>
<h3>$handler->get_timestamp();</h3>
<p>A convenience method that returns milliseconds since the Unix epoch. It is a simple wrapper around Time::HiRes::gettimeofday()</p>
<h2>Overridable Notification Methods</h2>
<h3>on_start ( $handler )</h3>
<p>on_start is called once immediately after $handler->poll is called.</p>
<p><dl>
<p><dd><b>$handler</b> Your HiPi::Interrupt::Handler instance.</dd></p></dl>
<h3>on_add ( $handler, $message )</h3>
<p>Called with the result of a call to $handler->add_pin</p>
<p><dl>
<p><dd><b>$handler</b> Your HiPi::Interrupt::Handler instance.</dd></p>
<p><dd><b>$message</b> An instance of <A HREF="interrupt_hipi_interrupt_message.htm">HiPi::Interrupt::Message</A></dd></p>
</dl>
<h3>on_remove ( $handler, $message )</h3>
<p>Called with the result of a call to $handler->remove_pin</p>
<p><dl>
<p><dd><b>$handler</b> Your HiPi::Interrupt::Handler instance.</dd></p>
<p><dd><b>$message</b> An instance of <A HREF="interrupt_hipi_interrupt_message.htm">HiPi::Interrupt::Message</A></dd></p>
</dl>
<h3>on_interrupt ( $handler, $message )</h3>
<p>Called with the result polling for interrupts on the monitored pins.</p>
<p><dl>
<p><dd><b>$handler</b> Your HiPi::Interrupt::Handler instance.</dd></p>
<p><dd><b>$message</b> An instance of <A HREF="interrupt_hipi_interrupt_message.htm">HiPi::Interrupt::Message</A></dd></p>
</dl>
<h3>on_continue ( $handler, $actions )</h3>
<p>Called periodically so that you may run code when no interrupts are occuring. Can be treated as a 'heartbeat' method. You can use $handler->get_timestamp to return milliseconds since the Unix epoch and store the value if you wish to carry out actions at a specific time offset.</p>
<p><dl>
<p><dd><b>$handler</b> Your HiPi::Interrupt::Handler instance.</dd></p>
<p><dd><b>$actions</b> The number of interrupts handled since the last call to on_continue.</dd></p>
</dl>
<h3>on_error ( $handler, $message )</h3>
<p>Called when an error occurs that is not specific to a particular $handler call.</p>
<p><dl>
<p><dd><b>$handler</b> Your HiPi::Interrupt::Handler instance.</dd></p>
<p><dd><b>$message</b> An instance of <A HREF="interrupt_hipi_interrupt_message.htm">HiPi::Interrupt::Message</A></dd></p>
</dl>
<h3>on_stop ( $handler, $message )</h3>
<p>Called with the result of a call to $handler->stop</p>
<p><dl>
<p><dd><b>$handler</b> Your HiPi::Interrupt::Handler instance.</dd></p>
<p><dd><b>$message</b> An instance of <A HREF="interrupt_hipi_interrupt_message.htm">HiPi::Interrupt::Message</A></dd></p>
</dl>
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