Hi Rick,
Regarding "local":
$| is a global* variable so you use local to isolate this change to only
where you need it.
To see what I mean, run this:
print "step1: $| \n";
{
local $| = 1;
print "step2: $| \n";
}
print "step3: $| \n";
and you'll get output:
step1: 0
step2: 1
step3: 0
while removing the 'local' you'll get
step1: 0
step2: 1
step3: 1
Does that answer your question?
Regarding autoflushing - that just means that it won't store the output in
a buffer and wait until the buffer is full (or until the process is
complete) before outputting it. This is a helpful description:
https://stackoverflow.com/questions/6303515/perl-1-what-is-this
<https://app.mailtag.io/link-event-v2?mt__id=c6c5700a-5861-11e8-824e-06cf19e8c68c&mt__url=https%3A%2F%2Fstackoverflow.com%2Fquestions%2F6303515%2Fperl-1-what-is-this>
Sorry I can't think of an easy way to replicate buffering in a short
script, but it certainly makes sense when responding to an HTTP request.
Andrew
* It's more accurate to say that $| is a package variable of the main
package, but "global" is close enough for this discussion :-)
On Tue, May 15, 2018 at 5:34 PM, Rick T <[email protected]> wrote:
> I’m very much a novice — familiar with Learning Perl but finding
> Intermediate Perl an uphill slog.
>
> The few lines below are from a subroutine that calls Template Toolkit. The
> commented out line I simply copied from Perl Template Toolkit (PTT); the
> line after it is what I replaced it with after seeing Perl Best Practices
> (PBP) show the auto flush variable handled this way. Both lines work,
> though I worry that the first one may not always work or else the use of
> local would not be recommended.
>
> I vaguely understand that local restricts the auto flushing, though I’m
> not sure how. Does local go out of scope when the TT is called? More
> broadly, do I actually need local? Do I actually need auto flushing? The
> authors of PTT and PBP assumed that persons reading their books would be
> fairly accomplished programmers — but I’m not. So can you educate me?
>
> # $| = 1;
> local $| = 1; # autoflush output
>
> print "Content-Type: text/html\n\n";
> my $tt = Template->new(
> ect.
>
> Many thanks!
> Rick Triplett
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--
Andrew Solomon
Perl Trainer, Geekuni http://geekuni.com/
[email protected] // +44 7931 946 062
