9.8 Void Functions as Statements
A function can be declared without a return value by using
in place of a return type. Note that the type
void may only be
used as a return type—arguments may not be declared to be of type
Usage as statement
A void function may be used as a statement after the function is declared; see the section on forward declarations for rules on declaration.
Because there is no return, such a usage is only for side effects, such as incrementing the log probability function, printing, or raising an error.
Special return statements
In a return statement within a void function’s definition, the
return keyword is followed immediately by a semicolon
;) rather than by the expression whose value is returned.