while they are blocked, the result is undefined,
unless the signal was generated by
.BR kill (2),
-.BR sigqueue (2),
+.BR sigqueue (3),
or
.BR raise (3).
.PP
.BR sigaction (2),
.BR signal (2),
.BR sigpending (2),
-.BR sigqueue (2),
.BR sigsuspend (2),
.BR pthread_sigmask (3),
+.BR sigqueue (3),
.BR sigsetops (3),
.BR signal (7)