Custom functions extend the library of PowerCenter functions. They are functions you create to use in transformation and workflow expressions. You create custom functions outside of PowerCenter with the Custom Functions API. To use the Custom Functions API, you must install the Informatica Development Platform from the Informatica Developer Community website.

The Custom Functions API uses the C programming language. You can share custom functions with others. Users can add the functions to their repository and use them like a PowerCenter transformation language function.

This chapter includes a sample function that demonstrates how to create and use a custom function with pushdown optimization. The steps in this chapter create the ECHO function. This function takes an argument as input and returns the input value to the user. The sample code for the ECHO function is in the

\CustomFunctionAPI\samples\echo

directory in the Informatica Development Platform installation.

You can also view a more complex sample custom function. The SampleLoanPayment custom function contains functions that are not available using C. SampleLoanPayment is in the

\CustomFunctionAPI\samples\loanpayment

directory in the Informatica Development Platform installation.