[vlc-devel] [PATCH 1/2] egl: Import GLES symbols with a direct library dlopen

Rémi Denis-Courmont remi at remlab.net
Tue May 22 17:52:27 CEST 2018

Le tiistaina 22. toukokuuta 2018, 18.35.45 EEST Thomas Guillem a écrit :
> On Tue, May 22, 2018, at 17:19, Rémi Denis-Courmont wrote:
> > Le tiistaina 22. toukokuuta 2018, 18.08.14 EEST Thomas Guillem a écrit :
> > > VLC uses eglGetProcAddress() to fetch core symbols.
> > 
> > There are no such bugs in the EGL plugin AFAICT.
> > 
> > There are a lot potential of issues in the GL(ES) plugin though.
> > GET_PROC_ADDR_CORE() seems counter-sensical.
> OK, the culprit is
> http://git.videolan.org/?p=vlc.git;a=commit;h=744ac6ec380ef07db7cb6f6ed07d4
> c9ba9708798 then
> We should not use eglGetProcAddress() to fetch core symbols but
> dlopen+dlsym.

No. There are no portable ways to get dlsym() in the dependent libraries. 
POSIX specifies no such thing. Linux has no such thing (neither RTLD_DEFAULT 
nor RTLD_NEXT match). FreeBSD seems to have something (NULL) but who cares.

The simplest solution is to check for GLX_ARB_get_proc_address v1.1 or 
EGL_KHR_get_all_proc_addresses respectively.

If you give a damn about the non-extended clients, then you need to reference 
the symbols directly in the GL provider. It will be tedious and so I must 
advise against it.

Rémi Denis-Courmont

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