condition variables and recursive_mutex

[nobody]

Hello  -
I've been working through the Boost.Threads example
code, I'm
new to the library, but i think i found a bug in the
monitor.cpp
example (boost_1_31_0/libs/thread/example/monitor.cpp) .  
When run using a recursive_mutex, the program hangs
more often than not.  It appears that the cuplrits are the
calls to cond.wait(lk).  For the recursive_mutex case,
it appears that
in some circumstances, these fall through without
actually waiting
for a change in the state of the lock lk.

Attached is an example which is somewhat simpler that
the one in
monitor.cpp, but yields the same problem.  Note that
I'm compiling on a redhat ws3 system, with:
  Thread model: posix
  gcc version 3.2.3 20030502 (Red Hat Linux 3.2.3-42)
and linking against libboost_thread-gcc-mt.so

Typical output as given is:
   sent 100, received 100
   sender waits 99, receiver waits 49944
I.e. close to 50k calls to cond.wait() in the receiver
thread)
When recompiling with "recursive_mutex" replaced by 
"mutex", the number of waits is on the order of the
number of
receives (i.e. in the range 0-100)

Any help/insight is appreciated.
Regards,
Bill Moser
billm@ll.mit.edu

[Roland Schwarz]

Logged In: YES 
user_id=541730

Can't tell what the problem was. I tested with boost RC_1_34
on linux with gcc 4.0.3 and could not observe the described
behaviour.