PHP produces "Document contains no data" error on page with:

dl("calendar.so");

and a call to jddayofweek();

Calendar shows up correctly as an extension from phpinfo(); and the extension_dir value is correctly shown from phpinfo().

./configure --with-apache=../apache_1.3.4 --with-mysql=/usr/local/mysql --with-imap --enable-sysvshm=yes --enable-sysvs
em=yes --with-config-file-path=/usr/local/apache/conf --enable-track-vars=yes

error in Apache log:

/usr/local/apache/bin/httpd: error in loading shared libraries
/usr/local/apache/libexec/calendar.so: undefined symbol: getParameters

calendar.so was compiled as per the instructions in the /dl/ source directory, and the extra flags were added to the PHP and Apache source as per the instructions.