Method signatures

Only methods which have arguments and return values which can be converted into EPL types may be exported. For some of the types, the equivalent EPL signature can automatically be deduced. For methods which only take and return those types, you do not need to supply the explicit type. For other types, you must provide the EPL signature when registering the function.

EPL type	C++ argument type	C++ return type	Notes
integer	int64_t	int64_t
string	const char *	const char *	You must only use const char * as a return type if it refers to a static string or a string whose lifetime is controlled outside of the function being returned from, such as one owned by a chunk. If you are constructing the string in the function, you must use std::string as the return type of the function instead.
string	std::string	std::string	Use std::string as the return type for your function unless you are certain that the lifetime of the string will outlast the function returning it.
float	double	double
boolean	bool	bool
decimal	decimal_t	decimal_t
chunk	const custom_t<T> &	custom_t<T>	Works for any class as the template parameter T.

EPL type	C++ argument type	C++ return type	Notes
context	int64_t	int64_t	int64_t will be deduced to integer, can be explicitly changed to context.
sequence<A>	const list_t &	list_t	Works for any sequence contents type.
dictionary<A, B>	const map_t &	map_t	Works for any dictionary contents type.
EventType	const map_t &	map_t	Works for any event type. The event is converted to a map_t where the key is of type string and the value is of type data_t. Keys are the names of the fields in the event.