SAP BUILT IN FUNCTIONS documentation, setup help and example usage

ARTICLE

Predefined Functions
ABAP provides a set of predefined functions. A predefined function returns a return value for one or more arguments. Predefined functions can be called by functions in certain operand positions.
Predefined functions can be called functionally at certain operand positions . When a predefined function is called at an
operand position , the function is executed before the operand is used and the return value of the predefined function is used as the operand, in accordance with its data type.
A predefined function is covered by a
functional method , regardless of how many arguments it has.

Predefined Functions - Syntax

Predefined Functions - Overview