dlopen()/festival problem

[Jan Kratochvil]

Hi Tim,

On Mon, 10 Nov 2008 14:21:22 +0100, Tim Niemueller wrote:
> So is it intended that the standard runtime linker and dlopen() work
> differently in initializing global variables of a library?

I did not see a problem with this.  BTW I would use `g++' instead of
`gcc -lstdc++'.

The problem is in the festival libraries build.  They use the default
visibility and their symbol `backtrace':
  ./speech_tools/siod/slib.cc
  LISP backtrace = NIL;
is being overriden by the glibc function `backtrace':
  /usr/include/execinfo.h
  extern int backtrace (void **__array, int __size) __nonnull ((1));
One apparently cannot write to a .text readonly section as it attempts to.

The package festival should be built with -fvisibility=hidden and specific
global functions/variables marked by `__attribute__ ((visibility("default")))'
as described in `man gcc' -fvisibility and
http://people.redhat.com/drepper/dsohowto.pdf .

As a temporary workaround you may use dlopen() flag RTLD_DEEPBIND.
BTW it is also more effective to use RTLD_LAZY than RTLD_NOW.


Regards,
Jan