Re: lt_dlopenadvise ignores advice

[Gary V. Vaughan]

Hi Anton,

Thanks for the report.

On 18 Apr 2008, at 11:47, Anton Ertl wrote:
> Here's the my_dlopenext example:
>
> #include <ltdl.h>
> #include <stdio.h>
>
> lt_dlhandle
> my_dlopenext (const char *filename)
> {
>  lt_dlhandle handle = 0;
>  lt_dladvise advise;
>
>  if (lt_dladvise_init (&advise)) {
>    fprintf(stderr,"lt_dladvise_init: %s\n",lt_dlerror());
>    exit(1);
>  }
>
>  if (lt_dladvise_ext (&advise)) {
>     fprintf(stderr,"lt_dladvise_ext: %s\n",lt_dlerror());
>    exit(1);
>  }
>
>  handle = lt_dlopenadvise (filename, &advise);

The documentation is wrong here (patch forthcoming), and your
program will work better if you use:

   handle = lt_dlopenadvise (filename, advise);

>  lt_dladvise_destroy (&advise);
>
>  return handle;
> }


You should be aware however, that opening libraries (as opposed
to modules) is not entirely portable.  For example Mac OS X has
foo.dylib for shared libraries that will be opened by the linker
at run time, and foo.so for modules that are openable with dlopen()
and equivalent.

On architectures with a runtime loader that can't handle dependent
libraries (for example a math.so module that was linked with -lm),
lt_dlopen() et. al. will portably open those dependency libraries
(eg libm.so) provided you installed and open the appropriate .la
file.

In other words, lt_dlopen("math.la") will automatically load libm.so
on those hosts that require it without forcing you to write non-
portable code.

Cheers,
        Gary
--
  ())_.              Email me: address@hidden
  ( '/           Read my blog: http://blog.azazil.net
  / )=         ...and my book: http://sources.redhat.com/autobook
`(_~)_

PGP.sig
Description: This is a digitally signed message part