You can call a function in an external library from a stored procedure or function.
You can call functions in a DLL under Windows operating systems and in a shared object on Unix.
The material that follows describes how to use the external function call interface. Sample external stored procedures, plus the files required to build a DLL containing them, are located in the following folder: %SQLANYSAMP17%\SQLAnywhere\ExternalProcedures.
External libraries called from procedures share the memory of the server. If you call an external library from a procedure and the external library contains memory-handling errors, you can crash the server or corrupt your database. Ensure that you thoroughly test your libraries before deploying them on production databases.
The interface described replaces an older interface, which has been deprecated. Libraries written to the older interface, used in versions before version 7.0.x, are still supported, but in any new development, the new interface is recommended. The new interface must be used for all Unix platforms and for all 64-bit platforms, including 64-bit Windows.
The database server includes a set of system procedures that make use of this capability, for example to send MAPI email messages.