(mysql.info) udf-compiling

 
 24.2.4.5 Compiling and Installing User-Defined Functions
 ........................................................
 
 Files implementing UDFs must be compiled and installed on the host
 where the server runs. This process is described below for the example
 UDF file `sql/udf_example.cc' that is included in the MySQL source
 distribution.
 
 The immediately following instructions are for Unix.  Instructions for
 Windows are given later in this section.
 
 The `udf_example.cc' file contains the following functions:
 
    * `metaphon()' returns a metaphon string of the string argument.
      This is something like a soundex string, but it's more tuned for
      English.
 
    * `myfunc_double()' returns the sum of the ASCII values of the
      characters in its arguments, divided by the sum of the length of
      its arguments.
 
    * `myfunc_int()' returns the sum of the length of its arguments.
 
    * `sequence([const int])' returns a sequence starting from the given
      number or 1 if no number has been given.
 
    * `lookup()' returns the IP number for a hostname.
 
    * `reverse_lookup()' returns the hostname for an IP number. The
      function may be called either with a single string argument of the
      form `'xxx.xxx.xxx.xxx'' or with four numbers.
 
 A dynamically loadable file should be compiled as a sharable object
 file, using a command something like this:
 
      shell> gcc -shared -o udf_example.so udf_example.cc
 
 If you are using `gcc', you should be able to create `udf_example.so'
 with a simpler command:
 
      shell> make udf_example.so
 
 You can easily determine the correct compiler options for your system
 by running this command in the `sql' directory of your MySQL source
 tree:
 
      shell> make udf_example.o
 
 You should run a compile command similar to the one that `make'
 displays, except that you should remove the -c option near the end of
 the line and add -o udf_example.so to the end of the line. (On some
 systems, you may need to leave the -c on the command.)
 
 After you compile a shared object containing UDFs, you must install it
 and tell MySQL about it. Compiling a shared object from
 `udf_example.cc' produces a file named something like `udf_example.so'
 (the exact name may vary from platform to platform). Copy this file to
 some directory such as `/usr/lib' that searched by your system's
 dynamic (runtime) linker, or add the directory in which you placed the
 shared object to the linker configuration file (for example,
 `/etc/ld.so.conf').
 
 The dynamic linker name is system-specific (for example, `ld-elf.so.1'
 on FreeBSD, `ld.so' on Linux, or `dyld' on Mac OS X). Consult your
 system documentation for information about the linker name and how to
 configure it.
 
 On many systems, you can also set the `LD_LIBRARY' or `LD_LIBRARY_PATH'
 environment variable to point at the directory where you have the files
 for your UDF.  The `dlopen' manual page tells you which variable you
 should use on your system. You should set this in `mysql.server' or
 `mysqld_safe' startup scripts and restart `mysqld'.
 
 On some systems, the `ldconfig' program that configures the dynamic
 linker does not recognize a shared object unless its name begins with
 `lib'. In this case you should rename a file such as `udf_example.so' to
 `libudf_example.so'.
 
 On Windows, you can compile user-defined functions by using the
 following procedure:
 
   1. You need to obtain the BitKeeper source repository for MySQL 5.0.
      See  installing-source-tree.
 
   2. In the source repository, look in the
      `VC++Files/examples/udf_example' directory. There are files named
      `udf_example.def', `udf_example.dsp', and `udf_example.dsw' there.
 
   3. In the source repository, look in the `sql' directory. Copy the
      `udf_example.cc' from this directory to the
      `VC++Files/examples/udf_example' directory and rename the file to
      `udf_example.cpp'.
 
   4. Open the `udf_example.dsw' file with Visual Studio VC++ and use it
      to compile the UDFs as a normal project.
 
 After the shared object file has been installed, notify `mysqld' about
 the new functions with these statements:
 
      mysql> CREATE FUNCTION metaphon RETURNS STRING SONAME 'udf_example.so';
      mysql> CREATE FUNCTION myfunc_double RETURNS REAL SONAME 'udf_example.so';
      mysql> CREATE FUNCTION myfunc_int RETURNS INTEGER SONAME 'udf_example.so';
      mysql> CREATE FUNCTION lookup RETURNS STRING SONAME 'udf_example.so';
      mysql> CREATE FUNCTION reverse_lookup
          ->        RETURNS STRING SONAME 'udf_example.so';
      mysql> CREATE AGGREGATE FUNCTION avgcost
          ->        RETURNS REAL SONAME 'udf_example.so';
 
 Functions can be deleted using `DROP FUNCTION':
 
      mysql> DROP FUNCTION metaphon;
      mysql> DROP FUNCTION myfunc_double;
      mysql> DROP FUNCTION myfunc_int;
      mysql> DROP FUNCTION lookup;
      mysql> DROP FUNCTION reverse_lookup;
      mysql> DROP FUNCTION avgcost;
 
 The `CREATE FUNCTION' and `DROP FUNCTION' statements update the `func'
 system table in the `mysql' database. The function's name, type and
 shared library name are saved in the table. You must have the `INSERT'
 and `DELETE' privileges for the `mysql' database to create and drop
 functions.
 
 You should not use `CREATE FUNCTION' to add a function that has
 previously been created. If you need to reinstall a function, you
 should remove it with `DROP FUNCTION' and then reinstall it with `CREATE
 FUNCTION'. You would need to do this, for example, if you recompile a
 new version of your function, so that `mysqld' gets the new version.
 Otherwise, the server continues to use the old version.
 
 An active function is one that has been loaded with `CREATE FUNCTION'
 and not removed with `DROP FUNCTION'. All active functions are reloaded
 each time the server starts, unless you start `mysqld' with the
 -skip-grant-tables option. In this case, UDF initialization is skipped
 and UDFs are unavailable.
Info Catalog
(mysql.info) udf-return-values
(mysql.info) adding-udf
(mysql.info) udf-security
automatically generated byinfo2html