subprogram is a program unit or intrinsic operation whose execution is
invoked by a subprogram call. There are two forms of subprogram: procedures
and functions. A procedure call is a statement
a function call is an expression and returns a value. The definition
of a subprogram can be given in two parts: a subprogram declaration defining
its interface, and a subprogram_body
defining its execution. [Operators and enumeration literals are functions.]
To be honest:
A function call is an expression,
but more specifically it is a name
Glossary entry: A subprogram is a section
of a program that can be executed in various contexts. It is invoked
by a subprogram call that may qualify the effect of the subprogram through
the passing of parameters. There are two forms of subprograms: functions,
which return values, and procedures, which do not.
Glossary entry: A function is a form
of subprogram that returns a result and can be called as part of an expression.
A procedure is a form
of subprogram that does not return a result and can only be called by
A callable entity
is a subprogram or entry
(see Section 9).
A callable entity is invoked by
; that is, a subprogram call or entry call.
is a construct that defines the action of a
call upon a callable entity: a subprogram_body
Ramification: Note that “callable
entity” includes predefined operators, enumeration literals, and
abstract subprograms. “Call” includes calls of these things.
They do not have callable constructs, since they don't have completions.
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