Passing an invalid pointer results in undefined behaviour.
The wrappers in libthr access some of the data pointed to by the arguments
in userland, so that an invalid pointer will cause a signal and not an
[EFAULT] error return.
Furthermore, if the [EFAULT] error occurs when the kernel is writing, it is
not a proper error in the sense that the call still commits (changing the
signal disposition or accepting the signal).
MFC after: 1 week
`sigprocmask', `sigaltstack', and `sigwait' as well as to the
prototypes of the apparantly unimplemented functions `sigtimedwait'
and `sigwaitinfo'. This complies with IEEE Std 1003.1-2001.
. use real function names as `.Nm' macro argument in NAME section. It allows
them to appear in apropos(1) or whatis(1) output.
. replace empty lines with `.Pp' macro.
. replace hardcoded standard names with their `.St' macro equivalents.
. sort cross references in SEE ALSO section
