Re: dlopen() without RTLD_GLOBAL

[James Henstridge <james daa com au>]

Tim Janik wrote:

> On 2 May 2002, Havoc Pennington wrote:
>
>  
>
> > Hi,
> >
> > gdk-pixbuf and the like should definitely not be using RTLD_GLOBAL, 
> > on platforms that support dlopen() with private symbols.
> > Using RTLD_GLOBAL has the effect of stuffing all those image libs into
> > our ABI, which kind of sucks.
> >
> > If we're doing a GLib 2.2, suggest that we add a
> > G_MODULE_LOCAL_SYMBOLS flag to GModuleFlags.
> >    
>
> one of the reasons to not have such a flag in the initial implementation
> was that not all systems do support user defined scope specification.
> gmodule-dl.c has more comments on this, and configure.in checks for
> RTLD_GLOBAL borkeness on at least OSF1/5.0.
> (the same holds for G_MODULE_BIND_LAZY, but isn't as much of a problem
> since lazy resolution of symbols is more of a hint and doesn't necessarily
> break things if not honoured).
>
> the demand to load modules with non-global symbols has popped up often
> enough to justify it's implementations though, but users (docs) need to
> be aware that G_MODULE_BIND_LOCAL (that's the flag name we should actually
> use) isn't correctly honoured on all systems.
>  
That doesn't sound like too much of a problem.  We already use a few 
features to limit what goes in the global symbol table that don't work 
correctly (such as the libtool -export-dynamic flag, which doesn't work 
on Linux).

James.