Procedure
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A procedure is a routine that does not return a value.
procedure
is a reserved word.
Prematurely leaving a procedure
In a procedure the routine exit
can be called in order to (prematurely) leave the procedure.
exit
may not be supplied with any parameters, since procedures do not return any value, but functions do.
Supplying a parameter to exit
inside a procedure definition will yield the compile-time error “Error: Procedures cannot return a value”.
Invocation
Procedure calls are statements. They may not appear in expressions, since they do not produce a value of any kind. The following example highlights all lines with procedure calls.
program procedureDemo(input, output, stderr);
var
x: longint;
procedure foo;
begin
exit;
inc(x);
end;
begin
x := 42;
foo;
writeLn(x);
end.
Note, that foo
contains unreachable code (inc(x)
is never executed because of the [unconditional] exit
).