书中不理解的地方mark一下

第九章 169页 关于错误处理的 edemo1

8> edemo1:start(true, {die,kill}).
Process b received {'EXIT',<0.73.0>,kill}
process b (<0.72.0>) is alive
process c (<0.73.0>) is dead

此时b为system process,它收到的C的信号是kill,为什么它还是alive?对比之前

4> edemo1:start(false, {die,kill}).
Process a received {'EXIT',<0.56.0>,killed} <-- ** changed to killed **
process b (<0.56.0>) is dead
process c (<0.57.0>) is dead
ok

它不为system process,收到来自c的kill,die掉了并且向a发出了killed信号
(这里为什么又没有记录b收到来自c的kill信号)?