<?php
$dateTime = new DateTime('2014-12-24'); // vánoce
$dateTime->modify('first day of this month'); // chci první den v měsíci
echo $dateTime->format('Y-m-d');
$dateTime->add(new DateInterval('P5D')); // Přidáme 5 dní
echo $dateTime->format('Y-m-d'); // správný výsledek je 2014-12-06
Warning: DateTime::modify(): Failed to parse time string (first day of this month) at position 10 (o): The timezone could not be found in the database in /in/C0H0p on line 4
2014-12-24
Fatal error: Call to undefined method DateTime::add() in /in/C0H0p on line 6
Process exited with code 255.
Output for 5.2.0 - 5.2.12
2014-12-25
Fatal error: Call to undefined method DateTime::add() in /in/C0H0p on line 6
Process exited with code 255.
Output for 5.0.0 - 5.0.5, 5.1.1 - 5.1.6
Fatal error: Class 'DateTime' not found in /in/C0H0p on line 3
Process exited with code 255.
Output for 5.1.0
Fatal error: fatal flex scanner internal error--end of buffer missed in /in/C0H0p on line 7
Process exited with code 255.
Output for 4.3.2 - 4.3.11, 4.4.0 - 4.4.9
Fatal error: Cannot instantiate non-existent class: datetime in /in/C0H0p on line 3
Process exited with code 255.
Output for 4.3.0 - 4.3.1
Fatal error: Cannot instantiate non-existent class: datetime in /in/C0H0p on line 3