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  GNU Pth - GNU Portable Threads

  PORTING
  =======

  SUCCESSFULLY TESTED PLATFORMS

  The Pth package was successfully tested on the following platforms
  (and should automatically adjust to other platforms, of course):

  __PLATFORM_ID________________ __MACHINE_CONTEXT__ __STACK__ __VERSION__
  i686-pc-freebsd3.1           | sjlj/ssjlj/sas    | down    | 1.2.0 [AUTHOR]
  i686-pc-freebsd3.3           | sjlj/ssjlj/sas    | down    | 1.2.0
  i686-pc-freebsd4.0           | sjlj/ssjlj/sas    | down    | 1.2b2
  i686-pc-freebsd2.2.8         | sjlj/ssjlj/sas    | down    | 1.2.0
  alpha-unknown-freebsd4.0     | sjlj/ssjlj/sas    | down    | 1.2b8
  i386-unknown-netbsd1.4       | sjlj/ssjlj/sas    | down    | 1.2b1
  sparc-unknown-netbsd1.4.1    | sjlj/ssjlj/sas    | down    | 1.2b8
  m68k-apple-netbsd1.4.1       | sjlj/ssjlj/sas    | down    | 1.2b5
  alpha-unknown-netbsd1.3.3    | sjlj/ssjlj/sas    | down    | 1.1.4
  i386-unknown-netbsd1.3.3     | sjlj/ssjlj/sas    | down    | 1.1.5
  i386-unknown-openbsd2.5      | sjlj/ssjlj/sas    | down    | 1.2b5
  i686-pc-linux-gnu            | sjlj/sjljlx/none  | down    | 1.2.0
  i586-pc-linux-gnulibc1       | sjlj/sjljlx/none  | down    | 1.2.0
  alphaev56-unknown-linux-gnu  | sjlj/ssjlj/sas    | down    | 1.2.0
  alphaev6-unknown-linux-gnu   | sjlj/ssjlj/sas    | down    | 1.2.0
  sparc-sun-solaris2.7         | mcsc/sc/mc        | down    | 1.2.0
  sparc-sun-solaris2.6         | mcsc/sc/mc        | down    | 1.2.0
  sparc-sun-solaris2.5         | mcsc/sc/mc        | down    | 1.1.4
  sparc-sun-solaris2.5.1       | mcsc/sc/mc        | down    | 1.2.0
  sparc-sun-sunos4.1.3_U1      | sjlj/ssjlj/ss     | down    | 1.1.4
  sparc-sun-sunos4.1.4         | sjlj/ssjlj/ss     | down    | 1.1.6
  i386-pc-sysv5uw7             | mcsc/sc/mc        | down    | 1.2.0
  i386-pc-sysv4.2uw2.1.3       | mcsc/sc/mc        | down    | 1.2.0
  i386-pc-sysv4.2uw2.1         | mcsc/sc/mc        | down    | 1.1.6
  rs6000-ibm-aix4.3.2.0        | mcsc/sc/mc        | down    | 1.1.5
  rs6000-ibm-aix4.2.1.0        | mcsc/sc/mc        | down    | 1.1.5
  powerpc-ibm-aix4.1.5.0       | mcsc/sc/mc        | down    | 1.1.5
  powerpc-ibm-aix4.2.1.0       | mcsc/sc/mc        | down    | 1.1.6
  hppa1.1-hp-hpux10.20         | sjlj/ssjlj/sas    | up      | 1.2.0
  hppa2.0-hp-hpux10.20         | sjlj/ssjlj/sas    | up      | 1.1.6
  mips-sgi-irix6.5             | mcsc/sc/mc        | down    | 1.2b1
  mips-sgi-irix6.2             | mcsc/sc/mc        | down    | 1.2b1
  i386-pc-isc4.0               | sjlj/sjljisc/none | down    | 1.2b2
  powerpc-apple-rhapsody5.5    | sjlj/ssjlj/sas    | down    | 1.2b3
  alphaev56-dec-osf4.0d        | mcsc/sc/mc        | down    | 1.2b6
  alphaev56-dec-osf4.0f        | mcsc/sc/mc        | down    | 1.2.0
  alphaev6-dec-osf5.0          | mcsc/sc/mc        | down    | 1.2.0

  HINTS FOR PORTING TO NEW PLATFORMS

  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.

