win32utils devel - May 2007 - Trying to get a good example for win32-mutex

Hi all,

I''ve been going through the various IPC modules for Win32Utils and
converting them to pure Ruby. I''m almost done with win32-mutex, but I
can''t get the example to work.  I keep getting this error:

C:/Documents and
Settings/djberge/workspace/win32-mutex/examples/mutex_test.rb:41:
undefined method `+'' for nil:NilClass
 (NoMethodError)
        from C:/Documents and
Settings/djberge/workspace/win32-mutex/examples/mutex_test.rb:38:in
`times''
        from C:/Documents and
Settings/djberge/workspace/win32-mutex/examples/mutex_test.rb:38

Here''s the updated mutex_test.rb file. I''m using the
win32/mutex.rb file
in CVS, win32-mmap 0.2.1 and win32-process 0.5.2:

##############################################################
# mutex_test.rb
#
# A test script for general futzing.  Modify as you see fit.
# This test script requires win32-process and win32-mmap.
##############################################################
MUTEXNAME = "This is a very long name"

require ''win32/mutex''
require ''win32/process''
require ''win32/mmap''
include Win32

pid = Process.fork

# child_1
if pid.nil?
   mm = MMap.open(''test'')
   mx = Win32::Mutex.open(MUTEXNAME)
   5.times{   
      mx.wait
      puts "child_1 wait "
      mm.gvalue += 123
      sleep 1
      mm.gvalue -= 123
      mx.release
      puts "child_1 release "
   }
   exit 1
end

pid2 = Process.fork

# child_2
if pid2.nil?
   mm = MMap.open(''test'')
   mx = Win32::Mutex.open(MUTEXNAME)
   4.times{
      mx.wait
      puts "child_2 wait "
      mm.gvalue += 456
      sleep 2
      mm.gvalue -= 456
      mx.release
      puts "child_2 release "
   }
   exit 1
end

#parent
mm = MMap.new(:size => 1024, :name => ''test'', :inherit
=> true)
mm.gvalue = 0
mx = Win32::Mutex.new(true, MUTEXNAME) #  named mutex object

3.times{
   mx.wait
   puts "parent wait"
   sleep 5
   printf("Value of GValue=%d\n", mm.gvalue)
   mx.release
   puts "parent release"
}

p Process.waitpid2(pid)
p Process.waitpid2(pid2)

It looks like the MMap.open(''test'') is working fine, but
it''s not
picking up the gvalue set in the parent for some reason.

Any ideas?

Thanks,

Dan


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> -----Original Message-----
> From: win32utils-devel-bounces at rubyforge.org 
> [mailto:win32utils-devel-bounces at rubyforge.org] On Behalf Of 
> Berger, Daniel
> Sent: Friday, May 04, 2007 8:57 AM
> To: Development and ideas for win32utils projects
> Subject: [Win32utils-devel] Trying to get a good example for 
> win32-mutex
> 
> 
> Hi all,
> 
> I''ve been going through the various IPC modules for 
> Win32Utils and converting them to pure Ruby. I''m almost done 
> with win32-mutex, but I can''t get the example to work.  I 
> keep getting this error:
> 
> C:/Documents and
> Settings/djberge/workspace/win32-mutex/examples/mutex_test.rb:41:
> undefined method `+'' for nil:NilClass
>  (NoMethodError)
>         from C:/Documents and 
> Settings/djberge/workspace/win32-mutex/examples/mutex_test.rb:38:in
> `times''
>         from C:/Documents and 
> Settings/djberge/workspace/win32-mutex/examples/mutex_test.rb:38
> 
> Here''s the updated mutex_test.rb file. I''m using the 
> win32/mutex.rb file in CVS, win32-mmap 0.2.1 and win32-process 0.5.2:
<snip>

Further review indicates that the problem is setting attributes to a
value of zero. I fired up two irb sessions, creating an mmap in one and
opening it in the other. When I do "mm.gvalue = 5", everything works
alright. However, if I set it to 0, I start getting:

ArgumentError: marshal data too short
        from
C:/ruby/lib/ruby/gems/1.8/gems/win32-mmap-0.2.0/lib/win32/mmap.rb:335:in
`load''
        from
C:/ruby/lib/ruby/gems/1.8/gems/win32-mmap-0.2.0/lib/win32/mmap.rb:335:in
`method_missing''
        from (irb):7

So, looks like a bug in win32-mmap. Disregard.

Dan


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privileged information. Unauthorized use of this communication is strictly 
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