[fpc-devel] assumed bug in the RTL with ARM v5 regarding loading dynamic libraries

[Thomas Schatzl]

Hi,

 [topic is about a compilation problem specific to qnap ARM/linux based
NASes using the heavily modded stock OS] 

On Wed, 2013-01-23 at 09:33 +0100, Michael Schnell wrote:
> 
> My project uses Synapse but features link problems and crashes when I 
> resolve same.
> Tracking this down:
> 
> Synapse uses the unit dynlibs
> 
> dynlibs uses the unit dl
> 
> dl does not have a "uses" clause, so the problem seems to be here.
> 
> When in a dedicated test project I just do "uses dl", I get the
> linker  message about _fini and _init, that I feature with any use of
> Synapse.
> 
> This can be resolved by
> {$I crti.o}
> and copying crti.o from /lib in my system to the project directory. 
> crti.o supposedly came with the libc-devel package that had been
> fetched when installing gcc.

  when you install libc-dev using ipkg on qnap (or install anything
using ipkg), *everything* is installed into the /opt subdirectory.

So if you copy and use some random crti.o from somewhere it won't work.
On my qnap, there is no crti.o in /lib for example.

You can specify the path where the linker searches for libraries (and
crt* files) using the -Fl command line parameter too. So you don't need
to copy around files at all.

On my arm qnap, after installing libc-dev, crti.o and friends are
located in /opt/arm-none-linux-gnueabi/lib

So, to compile your test program successfully, try the following
program:

program test;

uses cmem, dynlibs;

begin
  writeln('Hello');
end.

Compile with:

ppcarm -Fl/opt/arm-none-linux-gnueabi/lib test.pas


Hth,
Thomas

P.S.: It might be useful to start a bug report with the used compiler
version and platform, maybe with a compilable test program as simple as
the one above. Everything that you think might be needed to understand
the context and reproduce the issue.
Especially if you start a new thread, so that other readers not
following your qnap problems from the beginning in already X different
threads have a chance to understand and comment without reading 50 or so
emails.
Thanks.