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  • Perl 函数返回值的问题

    [root@jhoa 2015]# cat ping_dns.pl 
    use HTTP::Date qw(time2iso str2time time2iso time2isoz);
    use Net::Ping;  
    my @array=( "mbank.app.cz"
                 ); 
    while (1==1){  
    my $CurrTime = time2iso(time());  
            foreach $host (@array){  
            $p = Net::Ping->new("icmp");  
      
             open (A, ">>ping.log");  
            (  
    print A ("$CurrTime---$host is active.
    ") 
     
    )  if $p->ping($host,5);  
      
           open (B ,">>ping.log");  
           (   
    print B ("$CurrTime---$host is lost.
    ") ,
    print "xxxxxx
    " 
    )  unless $p->ping($host,5);  
            
       $p->close();  
     sleep(5)      
    }}  
    
    
    [root@jhoa 2015]# perl ping_dns.pl 
    xxxxxx
    xxxxxx
    xxxxxx
    xxxxxx
    
    
    1[root@jhoa 2015]# tail -10 ping.log 
    12015-02-26 11:48:58---mbank.app.cz is lost.
    12015-02-26 11:49:03---mbank.app.cz is lost.
    12015-02-26 12:23:36---mbank.app.cz is lost.
    12015-02-26 12:23:41---mbank.app.cz is lost.
    12015-02-26 12:23:46---mbank.app.cz is lost.
    12015-02-26 12:24:11---mbank.app.cz is lost.
    12015-02-26 12:24:16---mbank.app.cz is lost.
    12015-02-26 12:24:21---mbank.app.cz is lost.
    12015-02-26 12:24:26---mbank.app.cz is lost.
    
    
    为啥前面会打印出1呢? 因为1是print 的返回值
    
    [root@jhoa 2015]# cat a3.pl 
    (print "a",print "b");
    [root@jhoa 2015]# perl a3.pl 
    ba1[root@jhoa 2015]#
    
    
    [root@jhoa 2015]# cat a3.pl 
    (print "a", "b");
    [root@jhoa 2015]# perl a3.pl 
    ab[root@jhoa 2015]# 
    

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  • 原文地址:https://www.cnblogs.com/hzcya1995/p/13351854.html
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