PHP Calendar Functions Error
I was trying to use the PHP calendar API and immediately received this error message, “Fatal error: Call to undefined function cal_days_in_month()”. This error message means PHP was not compiled with the calendar extension.
Solution
The only solution to this error message and other similar error messages relating to the PHP calendar API requires PHP to be compiled with the calendar extension by adding “–enable-calendar” to the “configure command” as stated in the PHP documentation on the Calendar functions page.
How to Tell if the Calendar Extension is Installed
You can verify weather or not the PHP Calendar extension was compiled at install by using the phpinfo() function. When viewing the output of phpinfo() look under “Configure Command” just below “Build Date” and if you do not see “–enable-calendar” present then all PHP Calendar functions will not work.
Configure Example
./configure –with-mysql=/usr/local –with-mssql=/usr/local –with-apxs –with-zlib-dir=/usr/lib –with-libxml-dir=/usr/local –with-config-file-path=/var/www/conf –with-iconv=/usr/local/bin/iconv –enable-exif –-enable-mbstring –enable-calendar
