Perl的$|的范围是什么？ (OUTPUT_AUTOFLUSH)设置？

我有一个在安装了Perl 5.8.8的旧CentOS 5.6服务器上运行的Perl脚本.不幸的是,我无法升级操作系统或在此服务器上运行的Perl版本.

当我从命令提示符运行此脚本时,尽管有$| = 1;在脚本顶部的语句(在全局范围内),它似乎仍然缓冲输出到控制台(通过ssh会话).

写入日志文件和STDOUT都由函数执行,例如：

#!/usr/bin/perl
$| = 1;

&writelog("Started...");

# Do work with lots of writelog'ing

&writelog("...Done.");

exit(0);

sub writelog {

    # This is greatly simplified for the purpose of this question

    my ($logentry) = @_;
    my $logfile = "/var/log/tHelog.log";
    my $logline = "$logentry\n";
    print $logline;
    open (LOGFILE,">>$logfile");
    print LOGFILE,"$logline";
    close (LOGFILE);
}

是否为$|的值只影响当前范围内的输出,即在这种情况下脚本的全局范围？或者,在上面的示例中,是否应该通过writelog中的print语句立即刷新STDOUT / LOGFILE？

$| = 1;            # set autoflush on STDOUT
open LOGFILE,'>log';
my $fh = SELEct LOGFILE;   # change "SELEcted output chAnnel"
$| = 1;            # set autoflush on LOGFILE
SELEct $fh;        # restore STDOUT as "SELEcted output chAnnel"
$| = 0;            # turnoff autoflush on STDOUT