[Boost-users] scoped_lock lock&unlock

Subject: [Boost-users] scoped_lock lock&unlock
From: weii (willgunx_at_[hidden])
Date: 2010-03-19 00:36:29

Dear all,

I got a compiler(gcc 3.4.5) error while using boost.thread:

-----------------------------------------------------------------------------
g++ -IC:\Program Files\boost\boost_1_40 -O0 -g3 -Wall -c 
-fmessage-length=0 -omain.o ..\main.cpp
C:/Program 
Files/boost/boost_1_40/boost/thread/win32/basic_timed_mutex.hpp: In 
member function `bool boost::detail::basic_timed_mutex::timed_lock(const 
Duration&) [with Duration = bool]':
C:/Program Files/boost/boost_1_40/boost/thread/locks.hpp:353: 
instantiated from `bool boost::unique_lock<Mutex>::timed_lock(const 
TimeDuration&) [with TimeDuration = bool, Mutex = boost::mutex]'
C:/Program Files/boost/boost_1_40/boost/thread/locks.hpp:241: 
instantiated from `boost::unique_lock<Mutex>::unique_lock(Mutex&, const 
TimeDuration&) [with TimeDuration = bool, Mutex = boost::mutex]'
..\main.cpp:17:   instantiated from here
C:/Program 
Files/boost/boost_1_40/boost/thread/win32/basic_timed_mutex.hpp:118: 
error: no match for 'operator+' in 'boost::get_system_time() + timeout'
C:/Program Files/boost/boost_1_40/boost/date_time/time.hpp:140: note: 
candidates are: T boost::date_time::base_time<T, 
time_system>::operator+(const typename time_system::date_duration_type&) 
const [with T = boost::posix_time::ptime, time_system = 
boost::posix_time::posix_time_system]
C:/Program Files/boost/boost_1_40/boost/date_time/time.hpp:160: note: 
               T boost::date_time::base_time<T, 
time_system>::operator+(const typename time_system::time_duration_type&) 
const [with T = boost::posix_time::ptime, time_system = 
boost::posix_time::posix_time_system]
C:/Program Files/boost/boost_1_40/boost/operators.hpp:255: note: 
 
boost::date_time::date_duration<boost::gregorian::date_duration_rep> 
boost::operator+(const 
boost::date_time::date_duration<boost::gregorian::date_duration_rep>&, 
const boost::date_time::date_duration<boost::gregorian::date_duration_rep>&)
C:/Program 
Files/boost/boost_1_40/boost/date_time/posix_time/date_duration_operators.hpp:76: 
note:                 boost::posix_time::ptime 
boost::posix_time::operator+(const boost::posix_time::ptime&, const 
boost::gregorian::years&)
C:/Program 
Files/boost/boost_1_40/boost/date_time/posix_time/date_duration_operators.hpp:32: 
note:                 boost::posix_time::ptime 
boost::posix_time::operator+(const boost::posix_time::ptime&, const 
boost::gregorian::months&)
C:/Program 
Files/boost/boost_1_40/boost/date_time/date_duration_types.hpp:245: 
note:                 boost::gregorian::date 
boost::date_time::operator+(const boost::gregorian::date&, const 
boost::date_time::years_duration<boost::gregorian::greg_durations_config>&)
C:/Program 
Files/boost/boost_1_40/boost/date_time/date_duration_types.hpp:133: 
note:                 boost::gregorian::date 
boost::date_time::operator+(const boost::gregorian::date&, const 
boost::date_time::months_duration<boost::gregorian::greg_durations_config>&)
Build error occurred, build is stopped
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The following is my code:
-----------------------------------------------------------------------------------------------------------------------------
#include <boost/thread/thread.hpp>
#include <boost/thread/mutex.hpp>
#include <boost/bind.hpp>
#include <iostream>

boost::mutex io_mutex;

void count(int id)
{
        boost::mutex::scoped_lock lock(io_mutex,false);
        for (int i = 0; i < 10; ++i)
        {
                lock.lock();
                std::cout << id << ": " << i << std::endl;
                lock.unlock();
        }
}

int main(int argc, char* argv[])
{
        boost::thread thrd1(count, 1);
        boost::thread thrd2(count, 2);
        thrd1.join();
        thrd2.join();
        return 0;
}
-----------------------------------------------------------------------------
I know I can just abandon the lock() and unlock() function since the 
constructor and destructor will do them for me.
But I can't understand how this error occurs and why the compiler has 
something to do with basic_timed_mutex.

Anyone can give me some clues?
Thanks in advance.