POSIX siginfo

[Scott Long]

David Xu wrote:
> I am trying to implement POSIX sigqueue, while staring some code
> in machdep.c and trap.c, I found our si_code for siginfo structure
> is not in POSIX standard, all are machine dependent magical values
> pushed by CPU. POSIX lists all these standard codes:
> 
> http://www.opengroup.org/onlinepubs/009695399/basedefs/signal.h.html
> 
> /* codes for SIGILL */
> ILL_ILLOPC
> ILL_ILLOPN
> ILL_ILLADR
> ILL_ILLTRP
> ILL_PRVOPC
> ILL_PRVREG
> ILL_COPROC
> ILL_BADSTK
> 
> /* codes for SIGBUS */
> BUS_ADRALN
> BUS_ADRERR
> BUS_OBJERR
> BUS_RESERVED
> 
> /* codes for SIGSEGV */
> SEGV_MAPERR
> SEGV_ACCERR
> 
> /* codes for SIGFPE */
> FPE_INTOVF      1
> FPE_INTDIV      2
> FPE_FLTDIV      3
> FPE_FLTOVF      4
> FPE_FLTUND      5
> FPE_FLTRES      6
> FPE_FLTINV      7
> FPE_FLTSUB      8
> 
> /* codes for SIGTRAP */
> TRAP_BRKPT
> TRAP_TRACE
> 
> ...
> 
> Note that, NetBSD and Linux had already used the POSIX codes, should we
> use them too?
> 
> David Xu
> 

I'm by no means an expert in this work, but one thing that I will say is 
that you should be careful and look at the previous attempts here in 
FreeBSD.  I believe that Juli Mallett tried implementing signal queues a 
coupld of years ago but pulled them out because it turned out hard to 
make them reliable in low-memory situations.

Scott