Procedure

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).

See also

• Tutorial: procedures
• § “Procedure statements” in the Reference Guide
• § “Procedural types” in the Reference Guide

From the Free Pascal wiki, page "Procedure", as it stood on 2023-01-25 after a change by Kai Burghardt, out of the wiki's dump of 2024-05-26. Copyright stays with the author who wrote it, according to the old wiki's Licensing page. If you have concerns about this material, message the admin.