An external-language routine is a UDR that is written in an external language. The body of an external-language routine contains statements for operations such as flow control and looping, as well as special Informix library calls to access the database server. Therefore, you must use the appropriate compilation tool to parse and compile an external-language routine into an executable format.
The database server supports UDRs written in C and in Java.
To write routines in C, you need a C compiler. For information about how to write UDRs in C, refer to the IBM Informix: DataBlade API Programmer's Guide and the IBM Informix: DataBlade API Function Reference.
To write Java routines, you must have IBM Informix Dynamic Server with J/Foundation. You also need the Java Development Kit (JDK) to compile your Java routines.
For information about how to write Java UDRs, refer to the IBM Informix: J/Foundation Developer's Guide.