如何使用javascript替换变量模式(how to use javascript replace with variable pattern)

 为了彻底理解它，我们需要了解在linux中如何生成和传递信号。 
 
 当内核接收到任何信号请求时，它为该进程设置信号未决标志，提供的信号未被阻止。 现在在返回到用户模式之前，内核检查是否存在用于进程的非阻塞未决信号。 如果是的话，那么kernel在返回用户模式之前更愿意提供该信号。 现在回到你的问题： 
 
 
 
 如果有一个已经解锁的未决信号（比如SIGUSR1） 
 
 
 我假设信号（SIGUSR1）首先被阻止，然后解除阻塞。 在这种情况下，当用户尝试解除阻塞信号时，信号将在用户模式下恢复用户进程之前传输。 例如。 如果使用sigprocmask()来取消阻塞信号，则信号将在sigprocmask()返回之前传递。 
 
 
 
 将信号SIGUSR1通过调用sigprocmask（）传递给进程，该进程在保持SIGUSR1解除阻塞的情况下解除阻塞不同信号？ 
 
 
 如果多个未决信号被解除阻塞并准备发送，那么内核会选择具有最低信号数量的信号（当然，同步信号具有比异步信号更高的优先级）以首先发送。 

To understand it thoroughly we need to understand how signal are generated and delivered in linux.
 
When kernel receive any signal request it sets signal pending flag for the process, provided signal is not blocked. Now before returning to user mode kernel checks whether there are nonblocked pending signals are present for process or not. If yes, then kernel prefers to deliver that signal before returning to user mode. Now coming to your question:
 
 
 
if there is a pending signal (say SIGUSR1) that is already unblocked,
 
 
I am assuming that signal(SIGUSR1) is first blocked and later unblocked. In this case, when user made an attempt to unblock signal then signal will be delivered before user process resumes in user mode. For ex. if sigprocmask() is used to unblock signal then signal will be delivered even before sigprocmask() returns.
 
 
 
will the signal SIGUSR1 be delivered to the process with a call to sigprocmask() that unblocks a different signal while keeping SIGUSR1 unblocked?
 
 
If multiple pending signals are unblocked and ready to deliver then kernel picks the signal which has lowest signal number( of course, synchronous signals have higher priorities over asynchronous signal) to deliver first.