More examples and tweaks

* Signal dispatch() method now uses own pid as default value
* SharedData now updates checksum cache on set()

examples/shmdata.php

@@ -0,0 +1,34 @@
+<?php
+
+require_once __DIR__."/../vendor/autoload.php";
+
+use NoccyLabs\Ipc\Shm\SharedData;
+use NoccyLabs\Ipc\Key\FileKey;
+
+$key = new FileKey(__FILE__);
+$shm = new SharedData($key);
+
+// Set works as expected
+$shm->set("some.key", "Some value");
+// As does get
+echo $shm->get("some.key")."\n";
+
+// To make sure a value isn't modified while you are modifying it, use the third
+// parameter to set...
+//
+// Let's start at 123
+$shm->set("some.counter", 123);
+$counter = $shm->get("some.counter");
+echo "Counter is: ".$counter."\n";
+// And attempt to increase it
+$shm->set("some.counter", $counter + 1, true);
+$counter = $shm->get("some.counter");
+echo "Counter is: ".$counter."\n";
+
+// If the value is modified, the call will fail
+$shm2 = new SharedData($key);
+$shm2->set("some.counter", 345);
+if (!$shm->set("some.counter", $counter + 1, true)) {
+    echo "some.counter has been modified since last read\n";
+}
+