In EPL programs, you can use standard correlator plug-ins provided with Apama and you can also use correlator plug-ins that you define yourself. A correlator plug-in consists of an appropriately formatted library of C or C++ functions that can be called from within EPL. The event correlator does not need to be modified to enable or to integrate with a plug-in, as the plug-in loading process is transparent and occurs dynamically when required.

To write custom correlator plug-ins, see Writing Correlator Plug-ins.

When using a plug-in, you can call the functions it contains directly from EPL, passing EPL variables and literals as parameters, and getting return values that can be manipulated.