Adopey.146 net.bugs.4bsd utzoo!decvax!duke!mcnc!unc!dopey.smb Thu Mar 11 13:03:48 1982 sigset botch If a sighold is done, a subsequent sigset call will return SIG_HOLD rather than a routine address. An attempt to use this value will store a bad address -- 3! -- so that any occurrence of the signal will send the program flaming down the tubes. That is, a sequence like this will fail (miserably): sighold(SIGINT); ... s = sigset(SIGINT, myint); .... sigset(SIGINT, s); It's a problem because closed subroutine often like to take their own actions with knowing the current state of affairs. I've tripped over this in some versions of ucbmail.