If you want to simulate a crontask you must call this script once and it will keep running forever (during server uptime) in the background while "doing something" every specified seconds (= $interval):
ignore_user_abort(1); // run script in background
set_time_limit(0); // run script forever
$interval=60*15; // do every 15 minutes...
// add the script that has to be ran every 15 minutes here
sleep($interval); // wait 15 minutes
(PHP 4, PHP 5)
ignore_user_abort — Set whether a client disconnect should abort script execution
Sets whether a client disconnect should cause a script to be aborted.
When running PHP as a command line script, and the script's tty goes
away without the script being terminated then the script will die the
next time it tries to write anything, unless
value is set to
If set, this function will set the ignore_user_abort ini setting to the given
value. If not, this function will only return the previous setting without changing it.
Returns the previous setting, as an integer.
Example #1 A ignore_user_abort() example
// Ignore user aborts and allow the script
// to run forever
echo 'Testing connection handling in PHP';
// Run a pointless loop that sometime
// hopefully will make us click away from
// page or click the "Stop" button.
// Did the connection fail?
if(connection_status() != CONNECTION_NORMAL)
// Sleep for 10 seconds
// If this is reached, then the 'break'
// was triggered from inside the while loop
// So here we can log, or perform any other tasks
// we need without actually being dependent on the
PHP will not detect that the user has aborted the connection until an attempt is made to send information to the client. Simply using an echo statement does not guarantee that information is sent, see flush().
Theres no point in sending anything to the browser if the user does abort. Since the user aborted, the browser wont listen even if PHP did send information to the browser.
If you want to see if the user did abort, then use error_log() or some other form of logging to find out what happened, but dont rely on the output to the browser as the only method of checking ones data.
The script should output something to the browser in order to abort. If there is no output the script keeps on running.
Comment from Anonymous is not 100% valid. Time from sleep function is not counted to execution time because sleep delays program execution (see http://www.php.net/manual/en/function.sleep.php and comments). We tested it and it's true. Try this:
echo 'bye bye!';
It means, that if the loop most of the time will be at sleep (and in this case it probably be), then this script may be active for months or years even if you set time limit to one day.
use the spiritual-coder's code below with exreme caution and do not use it unless you are an advanced user.
first of all, such a code with no bypass point can cause infinite loops and ghost threads in server. there must be a trick to break out the loop.
i.e. you can use if (file_exists(dirname(__FILE__)."stop.txt")) break; in the loop so if you create "stop.txt", she script will stop execution.
also if you use set_time_limit(86400); instead of set_time_limit(0); your script will stop after one day.