An Overview of Installing UDFs
Because the MySQL source distribution contains a C file with a number of sample UDFs, you can easily start experimenting with UDFs right away. For this reason, you will learn about installing UDFs first. If you also have a knowledge of C and want to learn how to write your own functions, you will learn how to do this a little later today.
To use UDFs, your operating system must support dynamic loading (which will normally be the case with Unix and Linux).
Your mysqld should also have been compiled using --with-mysqld-ldflags=-rdynamic as an option to configure. So when running configure, the options would include (among other options):
# ./configure --with-mysqld-ldflags=-rdynamic
You may therefore ...