Boost C++ Libraries of the most highly regarded and expertly designed C++ library projects in the world. Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

This is an old version of boost. Click here for the latest version's documentation home page.

Class barrier



// In header: <boost/interprocess/sync/interprocess_barrier.hpp>

class barrier {
  // construct/copy/destruct
  barrier(unsigned int);

  // public member functions
  bool wait() ;


An object of class barrier is a synchronization primitive that can be placed in shared memory used to cause a set of threads from different processes to wait until they each perform a certain function or each reach a particular point in their execution.

barrier public construct/copy/destruct

  1. barrier(unsigned int count);

    Constructs a barrier object that will cause count threads to block on a call to wait().

  2. ~barrier();

    Destroys *this. If threads are still executing their wait() operations, the behavior for these threads is undefined.

barrier public member functions

  1. bool wait() ;

    Effects: Wait until N threads call wait(), where N equals the count provided to the constructor for the barrier object. Note that if the barrier is destroyed before wait() can return, the behavior is undefined. Returns: Exactly one of the N threads will receive a return value of true, the others will receive a value of false. Precisely which thread receives the return value of true will be implementation-defined. Applications can use this value to designate one thread as a leader that will take a certain action, and the other threads emerging from the barrier can wait for that action to take place.