Re: SIGIO, siginfo

[christos%zoulas.com@localhost (Christos Zoulas)]

On Jan 19, 12:57pm, yamt%mwd.biglobe.ne.jp@localhost (YAMAMOTO Takashi) wrote:
-- Subject: Re: SIGIO, siginfo

| linux saves the descriptor number.
| we can do the same if this interface is intended to be linux-compatibile.
| it has a good side effect to remove an XXXSMP in kpsignal.

Ouch, this seems to me like asking for trouble. What are the semantics if
a process does a dup2() to this file descriptor then, or closes it before
a queued sigio is delivered?

| i don't think SIGIO and its fcntl/ioctl are in POSIX.
| SIGPOLL is in POSIX, but it's for STREAMS which we don't have.

This is historically true, but I think at this point most implementations
consider them aliases. TOG's signal page does not associate it with streams
but TOG's ioctl page does (since it include <stropts.h>).

| > http://en.wikipedia.org/wiki/SIGPOLL
| 
| which part of the page are you reffering to?
| "On Linux, SIGIO is a synonym for SIGPOLL." ?

"On POSIX-compliant platforms, SIGPOLL is the signal thrown by computer
programs when asynchronous I/O event occurs."

What should we do about the inconsistent direction?

christos