HP SunSoft Pascal 4.0 - Manual (Page 281)

Pascal Preprocessor 257
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Comments
If the compiler encounters an %exit directive within an include file, it stops
processing the include file, but continues processing the source file in which
it is included. In effect, %exit is equivalent to an end-of-file marker.
When the compiler processes an %exit directive within an %if or %ifdef
construct, it closes all %if or %ifdef s before it stops processing the current
file.
Example
The %if Directive
The %if directive is a conditional branching directive.
Syntax
%if e xpression %then
.
.
%end if
The Pascal program,
exit_directive.p
program exit_directive(output);
begin
writeln('Hello, world!')
end. { exit_directive }
%exit
Everything after the %exit is ignored.
So you can put anything here.
The commands to compile and
execute
exit_directive.p
hostname% pc -xl exit_directive.p
hostname% a.out
Hello, world!