该实例必须增加计数器变量，并使用调用活动启动新的事件处理程序实例。

This instance simply has to increment the counter variable and start a new event handler instance using an invoke activity.

youdao

一种解决方法是增加一个变量，每创建一个新的线程该变量就加1，每终止一个线程该变量就减1，当该变量再次为零时，就关闭整个进程。

One way would be to increment a variable every time a thread is created, and decrement it whenever a thread terminates. When it reaches zero again, close the whole process.

youdao

所以perl 5增加了新的非全局变量。

So Perl 5 added new variables that aren't global.

youdao