如何解决以下错误“未打开的文件句柄上的readline()..."?

本文介绍了如何解决以下错误“未打开的文件句柄上的readline()..."?的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我该如何解决以下错误:

How would I solve the following error:

readline() on unopened filehandle UPPER at faStat2 line 86.

使用以下代码?

#!/usr/bin/perl
use strict;
use warnings;

...

my $cmd = $0;
$cmd =~ s#.*/##;

($#ARGV > 0) || die "Usage $cmd <tibcoUpperMDLog> <tibcoLowerMDLog> <outFile>\n\n";

open(my $UPPER, $ARGV[0]) || die "Unable to open $ARGV[0]\n";
open(my $LOWER, $ARGV[1]) || die "Unable to open $ARGV[1]\n";

...

while ($msg = <UPPER>) { getUpperBusTimeStampAndBatchSize(\$msg); } #This is the line that the error is complaning about

推荐答案

在这里，我同时介绍了实用和文体方面的变化.

Here I include both practical and stylistic chages.

#!/usr/bin/perl
use strict;
use warnings;

...

my $cmd = $0;
$cmd =~ s#.*/##;

die "Usage $cmd <tibcoUpperMDLog> <tibcoLowerMDLog> <outFile>\n\n"
  unless @ARGV > 2;

open my $upper, '<', $ARGV[0] or die "Unable to open $ARGV[0]\n";
open my $lower, '<', $ARGV[1] or die "Unable to open $ARGV[1]\n";

...

while ($msg = <$upper>) { getUpperBusTimeStampAndBatchSize(\$msg); }

实用:

3个arg open (更安全，更现代)
修复了对间接文件句柄的一致使用

风格:

使用或而不是花括号和 || (最不重要)
与 @ARGV 进行比较，而不是与 $#ARGV 进行比较(更具可读性，至少需要2个参数")
对词汇变量( my )使用小写字母

using or rather than braces and || (least important)
compare against @ARGV rather than $#ARGV (more readable, "need at least 2 args")
use lower case on lexical (my) variables

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