HP SunSoft Pascal 4.0 - Manual (Page 283)

Pascal Preprocessor 259
A
Comments
expression consists of a conditional variable and the optional boolean
operators and , or , and not . See the %else listing for examples of expression.
%ifdef is especially useful for determining whether or not a conditional
variable has been declared in an include file.
Example
See the example in “The %elseifdef Directive.”
The %include Directive
The %include directive inserts lines from the specified file in the input
stream.
Syntax
%include ' filename ' ;
Comments
When cppas encounters the %include directive, it inserts the lines from the
file name into the input stream.
Example
The program unit,
include_prog.p
program include_prog;
%include 'extern.h';
begin
global := 1;
writeln('From MAIN, before PROC: ',global);
proc;
writeln('From MAIN, after PROC: ',global);
end. { include_prog }