Question

我的初始值有问题。我有一个脚本，其方法有：

sub compare_with_terminal {
    use Term::Size::Any qw( chars pixels );
    my $columns = 0; 
    my $rows = 0;
    ($columns, $rows) = chars *STDOUT{IO};  

    print "Columns: ".$columns."\n"; #line 73
    print "Rows: ". $rows."\n";

    if($height > $columns || $width > $rows){
        print "Bigger than terminal: ";
        my $option = <>;
        chomp($option);
        if($option eq "N"){
            print "End.";
            exit 0;
        }
    }
}

如您所见，我在那里创建并初始化了两个值$columns和$rows。但是，当我运行这个脚本直到Unix我得到：

Use of uninitialized value $columns in concatenation (.) or string at ./perl/script.pl line 73 (#1) (W uninitialized) An undefined value was used as if it were already defined. It was interpreted as a "" or a 0, but maybe it was a mistake. To suppress this warning assign a defined value to your variables.

$rows有同样的错误。

这些错误说我没有初始化变量$columns，但我做到了。任何人都可以解释我并尝试解决这个问题吗？

Answer 1

There is a bug report for Term::Size::Any

在没有任何参数的情况下使用char会在linux上返回值（Term::Size::Any版本0.002）：

use warnings;
use strict;

use Term::Size::Any qw(chars);
my ($columns, $rows) = chars();
print "$columns $rows\n";

__END__

80 24

您已将$ column初始化为0，但在调用chars函数时会将其覆盖。

Perl - 即使在初始化值时“在连接（。）或字符串...中使用未初始化的值$”错误

1 个答案: