diff man/emodules.texi @ 880:beddd25fe24a

[xemacs-hg @ 2002-06-24 22:00:17 by youngs] 2002-06-17 Jerry James <james@xemacs.org> * emodules.texi (Loading other Modules): Describe why we do not use RTLD_GLOBAL. 2002-06-17 Jerry James <james@xemacs.org> * sysdll.c: Remove RTLD_GLOBAL initialization. * sysdll.c (dll_open): Do not use RTLD_GLOBAL.
author youngs
date Mon, 24 Jun 2002 22:00:25 +0000
parents 7d972c3de90a
children 2b58b7fd831c
line wrap: on
line diff
--- a/man/emodules.texi	Mon Jun 24 10:01:22 2002 +0000
+++ b/man/emodules.texi	Mon Jun 24 22:00:25 2002 +0000
@@ -483,6 +483,20 @@
 then their parents will also fail to load.  This does not include
 previous successful calls to @code{emodules_load} at the top level.
 
+@strong{Warning:} Modules are @emph{not} loaded with the
+@code{RTLD_GLOBAL} flag.  The practical upshot is that individual
+modules do not have access to each other's C symbols.  One module cannot
+make a C function call to a function defined in another module, nor can
+it read or set a C variable in another module.  All interaction between
+modules must, therefore, take place at the Lisp level.  This is by
+design.  Other projects have attempted to use @code{RTLD_GLOBAL}, only
+to find that spurious symbol name clashes were the result.  Helper
+functions often have simple names, increasing the probability of such a
+clash.  If you really need to share symbols between modules, create a
+shared library containing those symbols, and link your modules with
+that library.  Otherwise, interactions between modules must take place
+via Lisp function calls and Lisp variables accesses.
+
 @node Using ellcc, Defining Functions, Anatomy of a Module, Top
 @chapter Using @code{ellcc}
 @cindex @code{ellcc}