[Fwd: RE: Error with asmname]

11 Jul 2001

      I forward this message to the list to enable people to understand
the answer which is at the end.

-------- Original Message --------
Objet: RE: Error with asmname
Date: Tue, 10 Jul 2001 15:51:51 -0500
De: "Gloria, Jing" <j-gloria@ti.com>
A: "'Maurice Lombardi'" <Maurice.Lombardi@ujf-grenoble.fr>

Maurice,

pls be kind enough to run my test program in
your system and see if it compiles and links
correctly.  I have attached all three source
files and makefile needed.  Pls advise which
version of GPC you are using.

Thanks in advance for your assistance.  I will
be making a build of the latest GPC from source
tomorrow.

Regards,

Jing Gloria
Texas Instruments

---------------------------------------------------------

The problem is with try_hello.pas which is also a main pascal program.
The gpc-main trick is only to circumvent the case in which a C module
happens to define a function with name identical to the default gpc
main name.
But you cannot have two gpc mains because you have conflicts with
gpc main initializers and finalizers.
The solution is to write try_hello.pas as a unit, like this:

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unit try_hello;

INTERFACE

Var Testcode: integer; asmname 'testcode';
Procedure p_hello;

IMPLEMENTATION

Procedure p_hello;
begin
   Writeln ('PASCAL says: Hello, world.');
   Testcode := TestCode *2;
   Writeln ('Testcode = ', TestCode);
end;

End.

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Your makefile works then.

But this is still not the right way of doing.
You do not need makefiles with gpc

Rewrite try_main as

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program Hello (Output);

uses try_hello;

{$L c_hello.c}
procedure c_hello; external;

Begin
   Writeln ('Starting in main PASCAL module.');
   Writeln ('Calling C routine.');
   c_hello;
   Writeln ('Now back from C.');
   P_hello;
   WRITELN ('That is all folks!!')
End.

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then you can compile only the main with --automake

gpc try_main.pas -o try_main.exe --automake

gpc automatically compiles try_hello.pas and c_hello.c
becauses it has all informations needed in try_main by way
of the uses clause for pascal units and {$L } for c modules.

Maurice

BTW I use djgpp/ gpc 20010623 based on gcc 2.95.3

-- 
        Maurice Lombardi
Laboratoire de  Spectrometrie Physique,
Universite Joseph Fourier de Grenoble, BP87
38402 Saint Martin d'Heres Cedex     FRANCE
Tel: 33 (0)4 76 51 47 51
Fax: 33 (0)4 76 51 45 44
mailto:Maurice.Lombardi@ujf-grenoble.fr

{$gpc-main=Dummy}
Var
   Testcode: integer; asmname 'testcode'; 

Procedure p_hello;
begin
  Writeln ('PASCAL says: Hello, world.');
  Testcode := TestCode *2;
  Writeln ('Testcode = ', TestCode); 
end;

Begin
{ dummy block or else the GNU Pascal compiler
  will complain and generate a compile error.} 
End.

#include <stdio.h>

extern int testcode;

C_hello()
{
 	printf ("Hello, World -  from C \n\r");
	testcode = 12;
}

# Test Makefile for Pascal and C compiler.

..KEEP_STATE:
#
try2: try_main.o c_hello.o try_hello.o
	gpc -o try2 try_main.o try_hello.o c_hello.o

c_hello.o: c_hello.c
	gcc -O -c c_hello.c

try_hello.o: try_hello.pas
	gpc -c try_hello.pas

try_main.o: try_main.pas
	gpc -c try_main.pas

program Hello (Output);

procedure c_hello; external;

Procedure p_hello; external;

Begin
  Writeln ('Starting in main PASCAL module.');
  Writeln ('Calling C routine.');
  c_hello;
  Writeln ('Now back from C.');
  P_hello;
  WRITELN ('That is all folks!!')
End.