External references in GNU Pascal

1 Apr 1999

      I've just started using GNU Pascal to port some legacy code across to 
Windows95/NT.  I'm using DJGPP with the 19990118 beta copy of GPC.

Everything appears to be working fine until I get to the linking stage.  I'm 
getting unresolved references to Pascal procedures declared externally.

I suspect I must be getting something fairly basic wrong, but I can't even 
get an example from the GPC documentation to build successfully!

Suggestions would be gratefully received.

Mike Ainsworth

Example:
-- foobar.pas --
module foobar;

type footype = integer;
var foo : footype;

procedure setfoo(f : footype);
begin
  foo := f;
end;

function getfoo : footype;
begin
  getfoo := foo;
end;

end.

-- what.pas --
program what(output);

type footype = integer;

procedure setfoo(f : footype); external;
function getfoo : footype; external;

begin 
  setfoo(999);
  writeln(getfoo);
end.

-- Output --
gpc -o modtest.exe foobar.o what.o -lm -lgpc
Error: what.o: In function `program_What':
what.pas(8) Error: undefined reference to `Setfoo'
what.pas(10) Error: undefined reference to `Getfoo'

==========================================================================
                             Mike Ainsworth
    Praxis Critical Systems Limited, 20 Manvers Street, Bath BA1 1PX
Tel: +44 1225 466991     Fax: +44 1225 469006    Email: ma@praxis-cs.co.uk
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