S_HIPRI
if (arg & ~(S_INPUT|S_HIPRI|S_OUTPUT|S_MSG|S_ERROR|S_HANGUP))
if (arg & S_HIPRI)
*firstmsgsigs = S_HIPRI;
#define ALLSIG (S_INPUT|S_HIPRI|S_OUTPUT|S_MSG|S_ERROR|S_HANGUP|S_RDNORM|\
if (arg & ~(S_INPUT|S_HIPRI|S_MSG|S_HANGUP|S_ERROR|
~(S_INPUT|S_HIPRI|S_MSG|S_HANGUP|S_ERROR|
if (sevent & S_HIPRI) {
sevent &= ~S_HIPRI;