FPC compile for Caanoo (linux game console)

[Yakumo500]

Hi,
Maybe I will buy me a Caanoo (http://en.wikipedia.org/wiki/GP2X_Caanoo). On several internet sides it says that the plattform is Linux ARM (EABI=5). So I searched a little bit and found this page: http://www.opensubscriber.com/message/fpc-devel@lists.freepascal.org/14876597.html.
The problem is that I don't know how to use this files. I hope you can help me.

[Yakumo500]

Well, finally I got the compiler compiled (http://wiki.lazarus.freepascal.org/Setup_Cross_Compile_For_ARM). But now I try to link .a files, which were generated with gcc or g++. But the functions are not found. I compile my source via:

fpc -Tlinux -Parm Test.pas

And the following appears:

undefined reference to `DGE_Init'

I'm shure that this function exists in the .a file.
Has someone an idea?

//Edit: This is the function header:

Code: [Select]

function DGE_Init(): Integer; cdecl; external;

[Laksen]

Try
function DGE_Init(): Integer; cdecl; external name '_DGE_Init';

[Yakumo500]

The same message appears. I'm not quite sure if the a file is a MS or a GNU file.

[Leledumbo]

The cdecl modifier will automatically look for C mangled names (e.g. prepended with _), no need to specify it manually.

I'm shure that this function exists in the .a file.

Maybe... but how it's decorated? Please use objdump to see it. Anyway, I don't see anywhere you state to link with the .a. Do you use {$linklib xxx}? IMO it's better to use:

Code: [Select]

external 'libname' name 'mangled name'

[Yakumo500]

I've tried objdump. Output:

...
DGE_System.o:     file format pe-i386
rw-r--r-- 500/513 712256 Sep 16 19:33 2010 DGE_System.o
...

Also I've tried an other way:

Code: [Select]

program test;

{$mode DELPHI}

uses dynlibs, SysUtils;

type
  TDGE_Init = function(): Integer; cdecl;

var
  hLib: TlibHandle;
  DGE_Init: TDGE_Init;

begin
  hLib:= LoadLibrary('libdge20.so');
  @DGE_Init := GetProcedureAddress(hLib, 'DGE_Init');
  DGE_Init();
  @DGE_Init := nil;
  if hLib <> 0 then UnloadLibrary(hLib);
  hLib:= 0;
end.
But if I compile it under Windows for ARM this error occurs:
arm-gph-linux-gnueabi-ld: cannot find -ldl

(libdl.so exists in the search path)

[Leledumbo]

I've tried objdump. Output:

Seems like you don't use it as expected. Try this one instead:

Code: [Select]

nm <.a file> | grep DGE_Init

But if I compile it under Windows for ARM this error occurs:
arm-gph-linux-gnueabi-ld: cannot find -ldl

Try using -Fl compiler option

[Yakumo500]

Sorry I've never used objdump before. This is the output:

File STDIN:
0000002c T __Z8DGE_Initv

I'm already using the -Fl compiler option in fpc.cfg which points at the directory where libdl.so is.

[Yakumo500]

Ok it seems that i've forgotten -Fl  . Now I'm renaming the .so files. I hope it'll work.
Thank you for your support.

[Leledumbo]

File STDIN:
0000002c T __Z8DGE_Initv

Looks like a C++ (g++ to be precise) mangled symbol. FPC currently can't link directly to C++ modules due to non-standard mangling mechanism. "Flatten" in to C first, then link to it. Detailed explanation can be found here.

[Yakumo500]

Yeah I compiled it! 
I used the code I posted before with LoadLibrary. I had to replace some .so files which were pointing at other .so files.