On Wed, Jan 31, 2018 at 04:46:20AM +0000, Al Viro wrote: > MSG and REMOVE are never triggered, so it's all down to {WR{NORM,BAND},RDHUP}. Actually, POLLREMOVE is an amusing story (FSVO amusing): it's a part of UnixWare /dev/poll ABI. It had _not_ lasted in Linux - epoll_ctl() EPOLL_CTL_DEL is used for the same purpose. Chronology: Oct 29 2002: davidel introduces it into the tree (and defines for i386) Oct 31 2002: jgarzik has noticed broken alpha build and added definition within a few hours the same had been done for itanic (davidm) afternoon of the same day: Alan's merge of v850 adds definition there Nov 1 2002: rmk adds definition for arm Nov 2 2002: anton does the same for ppc64 Nov 2 2002: ak does the same for amd64 Nov 2 2002: davidel removes the sole user of that thing. But that, of course, does not stop the propagation of the (now and forever) useless definition - the same day it infects m68k; next day it's parisc and sparc. On Nov 8 it hits ppc32, Nov 17 - s390. In June 2003 mips gets it, in July sh is brought in with that thing already in it and the damn thing spreads to cris. And so it goes; the last flash of infection had been in 2007 when asm-generic/poll.h had been introduced. Its only user has lasted in the tree for four days. Definitions will probably stay forever...