Re^2: Experimental warnings with given/when

Second, I don't know why the warnings aren't going to where ever STDERR is being redirected to.

I was very curious to understand where Perl sends warning which is why I redirected STDERR. This is not something I do often, hence the deliberate division by zero runtime error to prove that it really was redirected.

#  STDOUT
given is experimental at test.pl line 17.
when is experimental at test.pl line 18.

# STDERR
Illegal division by zero at test.pl line 22.
[download]

So it seems that warnings are sent to STDOUT

Comment on Re^2: Experimental warnings with given/when Select or Download Code

Replies are listed 'Best First'.
Re^3: Experimental warnings with given/when by hippo (Archbishop) on Dec 01, 2020 at 11:37 UTC
Are you sure? With perl 5.20.3: `$ perl -wE 'given (1) {2}' given is experimental at -e line 1. Useless use of a constant (2) in void context at -e line 1. $ perl -wE 'given (1) {2}' 2> /tmp/err $ cat /tmp/err given is experimental at -e line 1. Useless use of a constant (2) in void context at -e line 1. $` [download] 🦛	[reply] [d/l]
Re^4: Experimental warnings with given/when by Bod (Parson) on Dec 01, 2020 at 12:24 UTC
Are you sure? I thought I was but I set up a little test to make sure I was sure and now I am not... `use feature "switch"; # Redirect STDERR open my $err_fh, '>', 'stderr.log'; STDERR = $err_fh; # Redirect STDERR open my $out_fh, '>', 'stdout.log'; STDOUT = $out_fh; my $i; given($i) { print "$i\n" when $i < 4; } # Prove STDERR is redirected my $error = 10 / 0;` [download] `Illegal division by zero at test.pl line 15.` is the only thing that is written to `STDERR` and `3` gets written to `STDOUT` but the following still gets displayed on the command prompt: `C:\Users\ian\Perl>perl test.pl given is experimental at test.pl line 10. when is experimental at test.pl line 11. C:\Users\ian\Perl>` [download] So I am not really sure what is going on with output streams as the warnings are on neither `STDERR` nor `STDOUT`. This is using Perl v5.28.1	[reply] [d/l] [select]
Re^5: Experimental warnings with given/when by hippo (Archbishop) on Dec 01, 2020 at 13:40 UTC
the following still gets displayed on the command prompt Those are compile-time warnings. They are generated before your run-time massaging of STDOUT and STDERR have taken effect. In contrast, I used the calling shell to set up the redirection so it is clear there that these warnings go to STDERR. 🦛	[reply]