linux中信号的术语

generated

  A signal is generated for a process (or sent to a process) when the event that causes the signal occurs

delivered

  We say that a signal is delivered to a process when the action for a signal is taken

pending

  During the time between the generation of a signal and its delivery, the signal is said to be pending

blocking

  A process has the option of blocking the delivery of a signal. 
  If a signal that is blocked is generated for a process, 
  and if the action for that signal is either the default action or 
  to catch the signal, then the signal remains pending for the process 
  until the process either (a) unblocks the signal
  or (b) changes the action to ignore the signal

action

  1 default
  2 catch
  3 ignore

参考：
          APUE