🚀 go-pugleaf

Drazen Kacar <dave@willfork.com> wrote in message news:<slrnb79ole.lql.dave@willfork.com>...
> Bart Smaalders wrote:
> 
> >     If you're not interposing on symbols in the library, the library may
> >     also be linked w/ -Bsymbolic,
> 
> Any reason why you're mentioning -Bsymbolic and not -Bdirect?

Because -Bdirect tells ld.so to remember where to find symbols (eg 
what library to search in), whereas -Bsymbolic tells ld to 
convert any references to global symbols that end up resolving at link
time to the current library to a local binding as if the symbol were static.
This cuts down on run-time overhead by avoiding the call through the PLT.

From the fine man page:

     -B direct
           Establishes direct binding  information  by  recording
           the relationship between each symbol reference and the
           dependency that provides the definition.  The  runtime
           linker  uses  this  information to search directly for
           the symbol in the associated  object  rather  than  to
           carry  out  its  default symbol search. Direct binding
           information can only be  established  to  dependencies
           specified with the link-edit. Thus, you should use the
           -z defs option. Objects that wish to interpose on sym-
           bols  in  a direct binding environment should identify
           themselves  as  interposers  with  the  -z   interpose
           option.  The  use of -B direct enables -z lazyload for
           all dependencies.

     -B symbolic
           In dynamic mode only. When building a  shared  object,
           binds  references  to  global symbols to their defini-
           tions, if  available,  within  the  object.  Normally,
           references to global symbols within shared objects are
           not bound  until  runtime,  even  if  definitions  are
           available,  so  that definitions of the same symbol in
           an executable or other shared object can override  the
           object's  own  definition.  ld will issue warnings for
           undefined symbols unless -z defs overrides.