      Interpretation Request #84 Topic: sigaction SA_RESTART
Relevant Sections: XSH sigaction  The restart behavior of
interruptible functions which use a timeout (such as nanosleep
and pselect) is not described in sufficient detail when
SA_RESTART is in effect. The duration of the timeout following
the restart varies greatly among implementations.  For example,
if a 600ms nanosleep call is interrupted by a signal after
200ms, and SA_RESTART was used, the observed possibilities on
restart are:  1) Do not restart the function, return EINTR
immediately. 2) Restart the timeout using the remaining time
interval (400ms). 3) Restart the timeout using the original full
time interval (600ms).   Applications should not depend on any
particular behavior in this situation.  To make this clear,
insert a new sentence before the sentence which starts with "If
the flag is not set...":  If an interruptible function which
uses a timeout is restarted, the the behavior and duration of
the timeout following the restart is undefi