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  GNU Pth - GNU Portable Threads

  PORTING
  =======

  This library was successfully tested on the following platforms (and
  should automatically adjust to other platforms, of course):

  __PLATFORM ID______________ __PLATFORM NAME______ _PTH_
  i686-pc-freebsd3.1          FreeBSD 3.1           1.1b6
  i586-pc-freebsd3.2          FreeBSD 3.2           1.0.5
  i686-pc-freebsd3.2          FreeBSD 3.2           1.0.0
  i586-pc-freebsd2.2.8        FreeBSD 2.2.8         1.0.2
  i685-pc-freebsd2.2.8        FreeBSD 2.2.8         1.0.0
  alpha-whatever-netbsd1.3.3  NetBSD/alpha 1.3.3    1.0b2
  i386-whatever-netbsd1.4     NetBSD/x386 1.4       1.0b1
  amiga-whatever-netbsd1.4    NetBSD/amiga 1.4      1.0b2
  sparc-whatever-openbsd      OpenBSD/sparc 2.x     1.0.5
  i386-whatever-bsdi          BSDI                  1.0.0
  i686-pc-linux-gnu2          RedHat 4.1            0.9.8
  i686-pc-linux-gnuredhat51   RedHat 5.1            1.0.4
  i586-pc-linux-gnu2          RedHat 5.2            1.1b5
  i686-pc-linux-gnu2          RedHat 6.0            1.0.0
  i486-pc-linux-gnu2          Debian 1.1            1.0b2
  i586-pc-linux-gnu2          Debian 2.1            1.0b2
  sun4d-sun-solaris2.5        Solaris 2.5           1.0.0
  sun4m-sun-solaris2.5.1      Solaris 2.5.1         1.0b2
  sun4u-sun-solaris2.6        Solaris 2.6           1.0.0
  sun4m-sun-solaris2.6        Solaris 2.6           1.0.0
  i86pc-sun-solaris2.6        Solaris 2.6           1.0.5
  sun4m-sun-solaris2.7        Solaris 2.7           1.1b6
  sun4u-sun-solaris2.7        Solaris 2.7           1.0.2
  i86pc-sun-solaris2.7        Solaris 2.7           0.9.8
  9000/735-hp-hpux9.01        HPUX 9.01             1.0.1
  9000/715-hp-hpux10.20       HPUX 10.20            1.0.0
  9000/735-hp-hpux10.20       HPUX 10.20            0.9.8
  9000/755-hp-hpux10.20       HPUX 10.20            1.0b8
  9000/778-hp-hpux10.20       HPUX 10.20            1.0.0
  9000/782-hp-hpux10.20       HPUX 10.20            1.0.3
  9000/819-hp-hpux10.20       HPUX 10.20            1.1.0
  alpha-dec-osf4.0            OSF/1 4.0             0.9.8
  alpha-dec-osf4.0b           OSF/1 4.0b            1.0.4
  A100-ibm-aix4.2             AIX 4.2               1.0b4
  8000-ibm-aix4.2             AIX 4.2               1.0.6
  9100-ibm-aix4.2             AIX 4.2               0.9.8
  4C00-ibm-aix4.2             AIX 4.2               1.0.1
  5C00-ibm-aix4.2             AIX 4.2               1.1.0
  8000-ibm-aix4.2             AIX 4.2               1.0.5
  4C00-ibm-aix4.3             AIX 4.3               0.9.8
  9300-ibm-aix4.3             AIX 4.3               1.0.6
  powerpc-ibm-aix4.3.2.0      AIX 4.3.2             1.0.4
  IP17-sgi-irix6.2            IRIX 6.2              1.0.0
  IP30/64-sgi-irix6.5         IRIX 6.5              1.1.0
  whatever-whatever-sco5      SCO Openserver 5.0.4  1.0.0
  i386-whatever-SCO_SV        SCO OpenServer 5.0.5  1.0.1
  i386-whatever-unixware2     UnixWare 2.1.3        1.0.0
  i386-whatever-unixware7     UnixWare 7.0          1.0b1
  i386-siemens-svr4           SINIX-D 5.41          0.9.8
  mips-siemens-svr4           ReliantUNIX-N 5.43    0.9.8
  m68k-whatever-AmigaOS3.1    AmigaOS 3.1           1.0.2
  m68k-apple-aux3             Apple Unix 3.x (c89)  1.1b4

  PORTING

  In case you're not able to use Pth on a new and esoteric platform,
  here are a few hints.

  Pth has only one part which perhaps has to be ported to new platforms: the
  machine context initialization, i.e. the function pth_mctx_set() in
  pth_mctx.c.  The exercise is to write a pth_mctx_set() function which
  initializes a `jmp_buf' (see setjmp(3)) with a given function and stack, so
  when the next longjmp(3) is done on this `jmp_buf' the function starts
  executing on the given stack.  
  
  Per default Pth uses a very tricky sigstack/sigaltstack() based approach for
  establishing this `jmp_buf' which is mostly portable to all major Unix
  platforms which support the involved POSIX functions. So the chance is very
  high that this approach also works for forthcoming platforms and no real
  porting is required. 
  
  When this approach should not work (for instance brain-dead GNU/Linux has a
  dummy sigstack/sigaltstack(), so we've no chance this way), then you've to
  provide an alternative implementation. This usually is done be fiddling
  around with the ingredients of a `jmp_buf' structure. For this look inside
  your /usr/include/setjmp.h (plus files it includes) and there especially for
  things like _pc or JB_PC (the program counter) and _sp or JB_SP (the stack
  pointer). Then write an alternative pth_mctx_set() function in pth_mctx.c.

  Currently, as mentioned, Pth requires such an alternative only under
  GNU/Linux where sigstack/sigaltstack() are dummy functions. Look at the
  GNU/Linux pth_mctx_set() variant in pth_mctx.c to get an impression what
  type of `jmp_buf' fiddling you perhaps have to do for esoteric platforms.
  Don't be confused by the fact that such specialized pth_mctx_set() functions
  are just a few lines long while the standard function is very large. That's
  all just needed for maximum portability.  The goal nevertheless only is to
  initialize a `jmp_buf' with PC and SP. That's all...

  Additionally see the INSTALL document for the --enable-mctx-XXX options.
  These can be used to easily try out mctx combinations on a platform, too.

