Good patterns for a C/C++ plugin-based system?

Question

When developing a C/C++ (=2?) plugin based framework with shared objects/dynamic libraries that need to support live swapping what examples would be helpful to look at for i

Answer 1

If you want cross-platform library loading without having to develop for each platform's API individually, libltdl may help.

Libtool provides a small library, called libltdl, that aims at hiding the various difficulties of dlopening libraries from programmers. It consists of a few headers and small C source files that can be distributed with applications that need dlopening functionality. On some platforms, whose dynamic linkers are too limited for a simple implementation of libltdl services, it requires GNU DLD, or it will only emulate dynamic linking with libtool's dlpreopening mechanism.

libltdl supports currently the following dynamic linking mechanisms:

• dlopen (Solaris, Linux and various BSD flavors)
• shl_load (HP-UX)
• LoadLibrary (Win16 and Win32)
• load_add_on (BeOS)
• NSAddImage or NSLinkModule (Darwin and Mac OS X)
• GNU DLD (emulates dynamic linking for static libraries)
• libtool's dlpreopen (see see Dlpreopening)

Boost.Extension seems to only support Windows PE dlls, UNIX ELF shared objects, and Mac OS X Mach-O bundles. Well, that may be sufficient for you...