text: //
  // detail/posix_signal_blocker.hpp
  // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  //
  // Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
  //
  // Distributed under the Boost Software License, Version 1.0. (See accompanying
  // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
  //
  
  #ifndef ASIO_DETAIL_POSIX_SIGNAL_BLOCKER_HPP
  #define ASIO_DETAIL_POSIX_SIGNAL_BLOCKER_HPP
  
  #if defined(_MSC_VER) && (_MSC_VER >= 1200)
  # pragma once
  #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
  
  #include "xviz/third_party/asio/detail/config.hpp"
  
  #if defined(ASIO_HAS_PTHREADS)
  
  #include <csignal>
  #include <pthread.h>
  #include <signal.h>
  #include "xviz/third_party/asio/detail/noncopyable.hpp"
  
  #include "xviz/third_party/asio/detail/push_options.hpp"
  
  namespace asio {
  namespace detail {
  
  class posix_signal_blocker
    : private noncopyable
  {
  public:
    // Constructor blocks all signals for the calling thread.
    posix_signal_blocker()
      : blocked_(false)
    {
      sigset_t new_mask;
      sigfillset(&new_mask);
      blocked_ = (pthread_sigmask(SIG_BLOCK, &new_mask, &old_mask_) == 0);
    }
  
    // Destructor restores the previous signal mask.
    ~posix_signal_blocker()
    {
      if (blocked_)
        pthread_sigmask(SIG_SETMASK, &old_mask_, 0);
    }
  
    // Block all signals for the calling thread.
    void block()
    {
      if (!blocked_)
      {
        sigset_t new_mask;
        sigfillset(&new_mask);
        blocked_ = (pthread_sigmask(SIG_BLOCK, &new_mask, &old_mask_) == 0);
      }
    }
  
    // Restore the previous signal mask.
    void unblock()
    {
      if (blocked_)
        blocked_ = (pthread_sigmask(SIG_SETMASK, &old_mask_, 0) != 0);
    }
  
  private:
    // Have signals been blocked.
    bool blocked_;
  
    // The previous signal mask.
    sigset_t old_mask_;
  };
  
  } // namespace detail
  } // namespace asio
  
  #include "xviz/third_party/asio/detail/pop_options.hpp"
  
  #endif // defined(ASIO_HAS_PTHREADS)
  
  #endif // ASIO_DETAIL_POSIX_SIGNAL_BLOCKER_HPP
  