Allow RTLD_GLOBAL to be optional

[Martin Baulig <martin home-of-linux org>]

Hi guys,

can you please add G_MODULE_BIND_PRIVATE or something like
this to GModuleFlags which will tell gmodule not to use
RTLD_GLOBAL ?

Yes, I really want to use g_module_symbol() for each symbol of
my shared library and yes, I really do not want to export its
symbols.

If you still don't see why this is necessary and why someone
may want such a "strange" feature, lemme explain:

I have several shared libraries, each of them containing some
global symbol, let's call it `foo'. If I don't give dlopen() the
RTLD_GLOBAL flag, I can load them all into my application and then
use dlsym() to get `foo'.

When I use gmodule and not dlopen/dlsym directly, this always
crashes - imagine the following situation:

Library A:

====
void
bar (void)
{
   g_message (G_STRLOC " - Library A");
}

void
foo (void)
{
   g_message (G_STRLOC " - Library A");

   bar ();
}
===

Library B:

====
void
bar (void)
{
   g_message (G_STRLOC " - Library B");
}

void
foo (void)
{
   g_message (G_STRLOC " - Library B");

   bar ();
}
===

If I use dlopen without RTLD_GLOBAL, loading both A and B into my application
and then calling both foo's via dlsym() works just fine.

With gmodule, B's foo() calls A's bar().

-- 
Martin Baulig
martin gnome org (private)
baulig suse de (work)