Re: [Boost-users] thread mutex problem

6 Sep 2010

      Kraus Philipp  writes:
...
I'm new with boost thread, I have some problems.
I have got two methods, one for writing and one for reading my data and I would
do this thread-safe.
I have tried to do this with boost::unique_lockboost::shared_mutex lock(...),
but I have created a deadlock.
For example my methods are called within the threads and set / get data to /
from a ublas matrix.
...
How can I do both methods in the correct way thread-safe?
boost::mutex m;

void setData( const size_t row, const size_t col, const size_t data) {
    boost::unique_lockboost::mutex lk(m);
    _matrix(row, col) = data 
}

void getData( const size_t row, const size_t col, size_t& a, size_t& b) {
    boost::unique_lockboost::mutex lk(m);
    a = _matrix(row, col);
    b = _matrix(col, row);
}

Once you've got the basics working, you can change the mutex to a
boost::shared_mutex and the lock in getData to a shared_lock rather than
a unique_lock if profiling determines that this is the bottle neck, *and*
the shared_mutex helps.

Anthony
-- 
Author of C++ Concurrency in Action     http://www.stdthread.co.uk/book/
just::thread C++0x thread library             http://www.stdthread.co.uk
Just Software Solutions Ltd       http://www.justsoftwaresolutions.co.uk
15 Carrallack Mews, St Just, Cornwall, TR19 7UL, UK. Company No. 5478976

Re: [Boost-users] thread mutex problem

Anthony Williams