[RPL/2] [Patch] Re: still a bug in multitasking

[BERTRAND Joël]

BERTRAND Joël wrote:
> BERTRAND Joël wrote:
>> DEMAINE Benoit-Pierre wrote:
>>> Playing with an old example attached:
>>>
>>> dhp at moon_gen_2:~/documents/programmation/rpl$ rpl -scd example_smp.rpl
>>> +++RPL/2 version 4.00pre8w (Tuesday 07/10/07, 23:57:24 CEST)
>>> +++Copyright (C) 1989 to 2006, 2007 BERTRAND Jol
>>> 99 bottles of beer on the wall,
>>> 99 bottles of beer.
>>> Take one down, pass it around,
>>> 98 bottles of beer on the wall.
>>>
>>> [...]
>>>
>>> 34 bottles of beer on the wall,
>>> 34 bottles of beer.
>>> Take one down, pass it around,
>>> 33 bottles of beer on the wall.
>>>
>>> +++System : Process error
>>>
>>> +++Information : Writing rpl-core file
>>> +++Information : Done
>>>
>>> It may fail and stop at various places: 99, 33, 34, 34, 29, 47, 41 ...
>> 	Thanks for report. Strange, I never saw this bug before, but I can 
>> reproduce it. I think that this bug comes from the new futex management 
>> in kernel. I will investigate.
> 
> 	I have found this bug, due to the new implementation of POSIX threads. 
> I think this bug didn't occur with old pthreads libs. Child process ends 
> before it has flushed its pipes to return value to its father.

	Fixed. Please replace src/gestion_processus.c by attached file and test 
with :

#!/usr/local/bin/rpl -sc
BOTTLES
<<
          // Child process is started.
          100 'RECURSIVE' detach
          -> PROC
          <<
                  do
                          // Parent waits for datas sent by child.
                          do PROC recv until end
                          -> OBJ
                          <<
                              OBJ
                              list-> drop dup " on the wall," +
                             disp "." +
                             disp "Take one down, pass it around," disp

                          if dup 1 same not then
                                  OBJ list-> drop
                          else
                                  1 "No more bottles of beer"
                          end
                          " on the wall." + disp drop "" disp
                      >>
                  until
                          1 same
                  end

                  // Parent waits for Child's death.
                  PROC wfproc
          >>
  >>

RECURSIVE
<<
          while
                  dup
          repeat
                  1 - dup dup ->str
                  if over 1 > then " bottles " else " bottle " end +
                  "of beer" + 2 ->list
                  // Child send datas to parent process.
                  send
                  // Recursive function is caught.
                  RECURSIVE
          end
  >>

	JKB
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