One of the pedagogical annoyances of poll() is the surfeit of POLL* values with distinctions that are not obviously apparent. Should I include POLLRDBAND in my events masks? How can I tell whether sockets generate priority data? It's kinda just handwaving.
With the removal of STREAMS and the putpmsg() interface for sending priority-band messages, it looks to me like the POLLRDNORM, POLLRDBAND, POLLWRNORM, and POLLWRBAND #defines could be marked as obsolescent. The POLL* namespace is, of course, still reserved so implementations would be free to providing them and having implementation-specific interfaces make use of priority bands in application-visible ways, but with no way for strictly compliant application to send or request priority-band data, it doesn't seem like POSIX's job to keep them around. Am I missing something, or can we clean up the poll() API documentation to make it easier to the majority of users? Philip Guenther
