perl 回调函数

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在计算机程序设计中，回调函数，或简称回调（Callback），是指通过函数参数传递到其它代码的，某一块可执行代码的引用。这一设计允许了底层代码调用在高层定义的子程序。没啥不好理解的呀，就是向函数的参数为   一个函数的引用呀。。[root@wx03 ~]# cat a2.pl use AE;   use AnyEvent;##定义watch    sub run {    my $code=shift;    my $t = AnyEvent->timer(        after    => 0,        interval => 1,        cb       => $code,    );my $cv = AnyEvent->condvar;  $cv->recv;        };sub test {print  "11111111111\n";};run(sub {test()});[root@wx03 ~]# perl a2.pl 1111111111111111111111[root@wx03 ~]# cat a2.pl use AE;   use AnyEvent;##定义watch    sub run {    my $code=shift;    my $t = AnyEvent->timer(        after    => 0,        interval => 1,        cb       => $code,    );my $cv = AnyEvent->condvar;  $cv->recv;        };sub test {print  "11111111111\n";};run(\&test);[root@wx03 ~]# perl a2.pl 1111111111111111111111[root@wx03 ~]# perl a2.pl 111111111111: callback must be a CODE reference or another callable object at /usr/local/perl/lib/site_perl/5.22.1/x86_64-linux/AnyEvent/Impl/EV.pm line 50.[root@wx03 ~]# cat a2.pl use AE;   use AnyEvent;##定义watch    sub run {    my $code=shift;    my $t = AnyEvent->timer(        after    => 0,        interval => 1,        cb       => $code,    );my $cv = AnyEvent->condvar;  $cv->recv;        };sub test {print  "11111111111\n";};run(&test);[root@wx03 ~]# perl a2.pl 111111111111: callback must be a CODE reference or another callable object at /usr/local/perl/lib/site_perl/5.22.1/x86_64-linux/AnyEvent/Impl/EV.pm line 50.
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