libffcall - foreign function call libraries

This is a collection of four libraries which can be used to build
foreign function call interfaces in embedded interpreters.

The four packages are:

    avcall - calling C functions with variable arguments

    vacall - C functions accepting variable argument prototypes

    trampoline - closures as first-class C functions

    callback - closures with variable arguments as first-class C functions
               (a reentrant combination of vacall and trampoline)


Installation instructions:

        mkdir builddir
        cd builddir
        ../configure --cache-file=config.cache
        make
        make check
        make install


Note: It is possible to do a build that produces shared libraries (by
passing --enable-shared to configure), but it makes little sense to do so:

1) The main function here is compiled from non-PIC assembly language.
   I.e. relocations would remain. The GNU linker supports shared libraries
   with relocations on x86 systems. But only on x86!

2) It is an overkill: libavcall, libvacall, libcallback have less than 1 KB
   of executable code (most of the real code is in the header files):

$ size libavcall.a
  text    data     bss     dec     hex filename
   420       0       0     420     1a4 avcall.o (ex libavcall.a)
    81       0       0      81      51 avcall-structcpy.o (ex libavcall.a)
$ size libvacall.a
  text    data     bss     dec     hex filename
   365       0       0     365     16d vacall.o (ex libvacall.a)
   203       0       0     203      cb misc.o (ex libvacall.a)
    81       0       0      81      51 vacall-structcpy.o (ex libvacall.a)
$ size libcallback.a
  text    data     bss     dec     hex filename
   379       0       0     379     17b vacall.o (ex libcallback.a)
   203       0       0     203      cb misc.o (ex libcallback.a)
    81       0       0      81      51 vacall-structcpy.o (ex libcallback.a)
   287       0       0     287     11f trampoline.o (ex libcallback.a)

When a shared library is loaded, you spend at least 4 KB for its code,
data and BSS. This is overkill for such a tiny library.

3) We don't do proper versioning of the resulting shared libraries (yet).
   Therefore it is possible that upgrading to a newer version of libffcall
   breaks existing binaries.


Files in this package:

    Documentation:

        README          this text
        COPYING         free software license
        PLATFORMS       list of supported platforms

    Source:

        avcall/*        the avcall package
        vacall/*        the vacall package
        trampoline/*    the trampoline package
        callback/*      the callback package

    Building:

        configure       configuration script
        configure.ac    autoconf source for the configuration script
        m4/*            auxiliary configuration scripts
        Makefile.in     Makefile master


Copyright notice:

Copyright 1993-1995 Bill Triggs <Bill.Triggs@inrialpes.fr>        (original avcall)
Copyright 1995-2016 Bruno Haible <bruno@clisp.org>                (everything)
Copyright 1997      Jörg Höhle <Joerg.Hoehle@gmd.de>              (m68k AmigaOS support)
Copyright 2000      Adam Fedor <fedor@gnu.org>                    (PowerPC MacOS support)
Copyright 2001-2012 Sam Steingold <sds@gnu.org>                   (build infrastructure)
Copyright 2001-2002 Gerhard Tonn <GerhardTonn@swol.de> <gt@debian.org> (s390 support)
Copyright 2004      Paul Guyot <pguyot@kallisys.net>              (PowerPC MacOS support)
Copyright 2005      Thiemo Seufer <ths@debian.org>                (MIPS EL support)
Copyright 2009      Max Lapan <max.lapan@gmail.com>               (ARM EL support)
Copyright 2010      Valery Ushakov <uwe@netbsd.org>               (SPARC64 improvements)

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.


Distribution:

git:
$ git clone git://git.savannah.gnu.org/libffcall.git
See https://savannah.gnu.org/git/?group=libffcall for more info.

Bug reports to:

  https://savannah.gnu.org/bugs/?func=additem&group=libffcall

Homepage:

  http://www.gnu.org/software/libffcall/