// Parameter "timeout" may be 0 for non-blocking operation, -1 for
// infinite waiting, or any positive timeout.
bool pop(message*& msg, m_host_t& from, double timeout);
// Parameter "timeout" may be 0 for non-blocking operation, -1 for
// infinite waiting, or any positive timeout.
bool pop(message*& msg, m_host_t& from, double timeout);