Re: Symbols relocatable using dlopen?

[Marcus Clyne <bu dot eugaia at gmail dot com>]

Hi Alan,

Thanks for your reply.

Alan Modra wrote:
> On Fri, Aug 28, 2009 at 12:58:06PM +0300, Marcus Clyne wrote:
>  
> > I have a function my_print () defined in my program, but in calling  
> > dlopen() I get the following error:
> >
> > undefined symbol: my_print
> >     
>
> my_print is likely not a dynamic symbol.  You can check with nm -D.
> There are a number of ways to make sure it is dynamic, eg. link
> your program against your dlopen'd shared lib with --no-add-needed,
> or use --dynamic-list.
>
>   

my_print isn't a dynamic symbol in the program.
Am I right in understanding that you mean that if I make the symbol 
dynamic in the main program, then it will be relocatable in the shared 
object when it's loaded, but if it's static, then it won't be?

If I understand the --no-add-needed option correctly, it's not 
appropriate for my situation as I don't know the names of the libraries 
when linking the program file.

I've tried using --dynamic-list=/file/path in the linker options.  In 
the /file/path I have 'my_print' in it on its own, but am getting 
'syntax error in dynamic list' messages.  I've also tried 'my_print,' 
with no luck.

I've looked in the man pages and online for the syntax for 
--dynamic-list files, but haven't found it yet.  Do you know what the 
format for the dynamic list files is?

Thanks,

Marcus.