declare

Ticks

A tick is an event that occurs for every N low-level statements executed by the parser within the declare block. The value for N is specified using ticks=N within the declare blocks's directive section.

The event(s) that occur on each tick are specified using the register_tick_function(). See the example below for more details. Note that more than one event can occur for each tick.

Example 11-1. Profile a section of PHP code <?php // A function that records the time when it is called function profile ($dump = FALSE) { static $profile; // Return the times stored in profile, then erase it if ($dump) { $temp = $profile; unset ($profile); return ($temp); } $profile[] = microtime (); } // Set up a tick handler register_tick_function("profile"); // Initialize the function before the declare block profile (); // Run a block of code, throw a tick every 2nd statement declare (ticks=2) { for ($x = 1; $x < 50; ++$x) { echo similar_text (md5($x), md5($x*$x)), "<br />;"; } } // Display the data stored in the profiler print_r (profile (TRUE)); ?>

The example profiles the PHP code within the 'declare' block, recording the time at which every second low-level statement in the block was executed. This information can then be used to find the slow areas within particular segments of code. This process can be performed using other methods: using ticks is more convenient and easier to implement.

Ticks are well suited for debugging, implementing simple multitasking, backgrounded I/O and many other tasks.

See also register_tick_function() and unregister_tick_function().