PHP Fatal error: Call to undefined function date_format() in date_api

• Drupal 6.19
• PHP 5.1.6
• PostgreSQL 8.1
• centOS 5

Having upgraded from Drupal 5.20 it's taken weeks to track down and fix an event/calendar problem which appears to be all down to the version of PHP. Unfortunately this cannot be upgraded because the production website is on a managed server. Many replies to comments have said upgrade to PHP 5.2 to which many have replied it's not an option - same reason as me. Have also spoken to web host, but there's no plan to upgrade their RHEL5 in the immediate future.

But tonight... bingo!

I am requesting that the date_api module be modified to check which version of PHP is being used.

Line: 655 > 657 in date_api.module

#  if (get_Class($date) != 'DateTime') {
#    $date = new DateTime($date);
#  }

Be updated with ...

if (phpversion() >= 5.2 && get_Class($date) != 'DateTime') {
  $date = new DateTime($date);
}

This will hopefully resolve many of those struggling to find a fix with the white screen of death that you may see. Checking the error logs revealed:

PHP Fatal error: Call to undefined function date_format() in date_api

The source for this fix was buried down a thread at http://drupal.org/node/882980

And the credit all goes to #24 Posted by Durrok on August 23, 2010 at 6:50pm

Hope this helps save others weeks of tearing their hair out with the same installation set up I have to use ;-)