Ada Reference Manual (Ada 2022)

1.3.2 Subprograms and their Properties

function

form of subprogram that returns a result and can be called as part of an expression

overriding operation

operation that replaces an inherited primitive operation

Note: Operations can be marked explicitly as overriding or not overriding.

postcondition

assertion that is expected to be True when a given subprogram returns normally

precondition

assertion that is expected to be True when a given subprogram is called

procedure

form of subprogram that does not return a result and can only be invoked by a statement

subprogram

unit of a program that can be brought into execution in various contexts, with the invocation being a subprogram call that can parameterize the effect of the subprogram through the passing of operands

Note: There are two forms of subprograms: functions, which return values, and procedures, which do not.