Ken, you are the person advocating for me to use perlbrew ;-) so I am going to toss this your way and ask if you have any suggestions. I had perlbrew installed for months but there was some initial trouble getting it to work and so I never built any perl using it. Today I tried again and unfortunately some tests failed:

  Failed tests:  269-270, 275-276, 281-282, 287-288, 293-294
                299-300, 305-306, 311-312, 317-318, 323-324
                329-330, 335-336, 341-342, 347-348, 353-354
                359-360, 365-366, 371-372, 377-378, 383-384
                389-390, 395-396, 401-402, 407-408
  Non-zero exit status: 48
Files=2930, Tests=1351653, 907 wallclock secs (146.98 usr 139.20 sys + 1447.43 cusr 1224.94 csys = 2958.56 CPU)
Result: FAIL
Finished test run at Sat Aug  2 14:05:14 2025.
make: *** (GNUmakefile:853: test_harness) Error 1
perl-5.42.0 is successfully installed.  <-- ha ha
perl-5.42.0 is not installed  <-- ha ha

I naturally went for the newest perl release, 5.42.0.:

perlbrew install -v -j 5 --switch --thread --multi --64all perl-5.42.0

Any ideas? Try with an older release maybe?

    — Soren

FWIW, I have no experience with Perlbrew. I don't see the point of it. I actually hate it - which is quite irrational (isn't all hatred ?) given that I've never tried it.
For mine, I just build perl in the normal way by running 'Configure', 'make test', 'make install' and finally 'make distclean' (in prepraration for the next build, of a different configuraton).

So, for my stock standard build of perl-5.42.0, I started with:
sh Configure -des -Dusethreads -Dusemultiplicity -Dprefix=/cygdrive/c/cygperl-5.42.0-d -Dlibpth=/lib/gcc/x86_64-pc-cygwin/11

For my -Duselongdouble build:
sh Configure -des -Dusethreads -Dusemultiplicity -Dprefix=/cygdrive/c/cygperl-5.42.0-ld -Dlibpth=/lib/gcc/x86_64-pc-cygwin/11 -Duselongdouble

And for my -Dusequadmath build:
sh Configure -des -Dusethreads -Dusemultiplicity -Dprefix=/cygdrive/c/cygperl-5.42.0-q -Dlibpth=/lib/gcc/x86_64-pc-cygwin/11 -Dusequadmath

I think I need that '-Dlibpth' switch only because I want the quadmath library to be automatically found for all 3 builds.
For you, I think that directive would end with "13" instead of "11", but I'm only guessing ... and it might even be the case that, with your gcc-13, there's no need for that directive any more.

I regularly hit a failing test in t/porting/exec-bit.t, and in one other file (I forget which).
My Cygwin installation is a few years old - your Cygwin might fare better.
Those couple of failures don't bother me at all, and I've not reported them.

I select which perl I want to use by running (eg):
export PATH=/cygdrive/c/cygperl-5.42.0-d/bin:$PATH

If I want to switch to a different perl I just run (eg):
export PATH=/cygdrive/c/cygperl-5.42.0-q/bin:$PATH

On cygwin I have (double, longdouble and quadmath builds) of perls 5.36.0, 5.38.0, 5.40.0, and 5.42.0.
It's easy to handle, and I'm not about to bother with perlbrew.
Of course, those who do want to use perlbrew for whatever purpose, are entitled to do so.

Cheers,
Rob

It's been quite a few years since I set up Cygwin & Perlbrew. I'll provide what information I can: some current and some quite old.

My current Win10 — what I see when I start cmd.exe:

Microsoft Windows [Version 10.0.19045.6159]
(c) Microsoft Corporation. All rights reserved.

C:\Users\ken>
[download]

My current system (Cygwin) information:

$ uname -a
CYGWIN_NT-10.0-19045 titan 3.6.4-1.x86_64 2025-07-15 07:55 UTC x86_64 
+Cygwin
[download]

I originally set up Cygwin using the installer on the Cygwin site; I have updated that many times over the years (currently at 3.6.4).

As far as I remember, I originally set up Perlbrew from the instructions on that page:

For a quick installation, do this:

\curl -L https://install.perlbrew.pl | bash
[download]

It would appear that I did this about six years ago and haven't changed it since:

$ which perlbrew
/home/ken/perl5/perlbrew/bin/perlbrew

$ ls -l /home/ken/perl5/perlbrew/bin/perlbrew
-rwxr-xr-x 1 ken None 1316905 Jul 26  2019 /home/ken/perl5/perlbrew/bi
+n/perlbrew
[download]

I've been installing Perl versions using instructions a little further down on that page. This is what I used yesterday.

To install the latest stable release ...

perlbrew install perl-5.42.0
perlbrew switch perl-5.42.0
[download]

This installed Perl v5.42.0 cleanly on the first run; no test or other errors.

I've also installed other Perl versions, stable & development, over the years:

$ perlbrew list
 * perl-5.42.0
   perl-5.40.0
   perl-5.39.3
   perl-5.38.0
   perl-5.36.0
   perl-5.34.0
   perl-5.33.5
   perl-5.32.0
   perl-5.30.0
[download]

I really can't help with the error information that you've posted. You may want to start (almost) from scratch:

1. Get Cygwin up-to-date. I do this by downloading the Cygwin Installer (setup-x86_64.exe) then running that from Win10: File Explorer.
2. Reinstall perlbrew using the instructions shown above.
3. Reinstall Perl v5.42.0 using the instructions shown above.

I'll also advise you to run the latest setup-x86_64.exe regularly — I generally aim to do this weekly so that it only takes some tens of minutes — otherwise you may find it takes hours if left for an extended period of time.

Good luck!

— Ken