A.pl调用另一个程序B.pl,为何在B.pl结尾需要返回一个值?

A.pl调用另一个程序B.pl,为何在B.pl结尾需要返回一个值?

如果不返回,就会提示出错,为什么呢?
怎么调用的?当成模块?还是`./B.pl`; 或者system("./B.pl");
require B.pl

B.pl最后一行写1就行了
不知道为什么哦
不一定是1,最后一条语句返回真就行(当然是在确定返回真的情况).

perldoc -f require

QUOTE:
...The file must return true as the last statement to indicate successful execution of any initialization code, so it's customary to end such
               a file with "1;" unless you're sure it'll return true otherwise.  But it's better just to put the "1;", in case you add more statements....