I needed to add a sleep to a PHP process, but I didn’t want to waste a whole second on each cycle. That’s usleep:

<?php
        date_default_timezone_set('America/New_York');

        $t = microtime(true);
        $micro = sprintf("%06d",($t - floor($t)) * 1000000);
        $d = new DateTime( date('Y-m-d H:i:s.'.$micro, $t) );

        print $d->format("Y-m-d H:i:s.u") . "\n";                                                                       
        usleep(100000);

        $t = microtime(true);
        $micro = sprintf("%06d",($t - floor($t)) * 1000000);
        $d = new DateTime( date('Y-m-d H:i:s.'.$micro, $t) );

        print $d->format("Y-m-d H:i:s.u")  . "\n";                                                                      
        sleep(1);
        $t = microtime(true);
        $micro = sprintf("%06d",($t - floor($t)) * 1000000);
        $d = new DateTime( date('Y-m-d H:i:s.'.$micro, $t) );

        print $d->format("Y-m-d H:i:s.u")  . "\n";                                                                      
?>

Run the script, and you’ll see sub-second sleeps.

[tempuser@564240601ac2 /]# php testSleep.php
2020-07-09 14:06:20.641449
2020-07-09 14:06:20.741952
2020-07-09 14:06:21.742347

We needed to modify a shared function to include additional information … but didn’t want to coordinate changing all of the calls to the function as one change. Simplest way to accomplish that was to set a default value for the new parameter — either to NULL and just not do the new thing when the parameter is NULL or some value that indicates that we’re not yet gathering that data.

<?php

function testFunction($strOldParameter, $strNewParameter=NULL){
     echo "The old parameter is |$strOldParameter|\n";
     if($strNewParameter){
          echo "The new parameter is |$strNewParameter|\n";
     }
}

testFunction("first", "second");
testFunction("justFirst");

?>

There’s no straight-forward way to handle execution timeout in PHP 5.x — it’s not like you can try/except or something. The execution time-limit is exceeded, the program terminates. Which, thinking from the perspective of the person who maintains the server, is a Good Thing … bugger up the ‘except’ component and now that becomes an infinite loop.

But I’m looking to throw a “pretty” error to the end user and have them try again with a data set that will take less time to process. Turns out, you can use a shutdown function to display something other than the generic PHP time limit exceeded page.

<?php

function runOnShutdown(){
     $arrayError = error_get_last();

     if( substr($arrayError['message'], 0, strlen("Maximum execution time of")) === "Maximum execution time of"   ){
          echo "<P>Maximum execution time";
     }
     elseif($arrayError){
          print_r($arrayError);
     }
}

function noOp($iInteger){
     for($z = 0; $z < $iInteger; $z++){
          $a = $iInteger * $iInteger;
     }
     return $iInteger;
}

register_shutdown_function('runOnShutdown');
ini_set('display_errors', '0');
ini_set('max_execution_time', 2);

// for($i = 0; $i < 10; $i++){
for($i = 0; $i < 10000; $i++){
     $j = noOp($i);
     print "<P>$j</P>\n";
}
print "<P>Done</P>\n";

?>

And the web output includes a customized message because the max execution time has been exceeded.