I just built perl v5.40.0 from source on Ubuntu, using the same steps as last time, without any build problems.

Note that perl v5.34 added try/catch syntax, inspired by Syntax::Keyword::Try:

use feature 'try';
try {
   do_a_thing();
}
catch ( $e ) {
   warn "It failed - $e";
}
[download]

while perl v5.36 further added finally blocks to try/catch, also inspired by Syntax::Keyword::Try:

use feature 'try';
try {
   do_a_thing();
}
catch( $e ) { ... }
finally {
   cleanup();
}
[download]

While updating my try-catch sample program from perl v5.38.2 to v5.40.0, I noticed that while try-catch feature is no longer experimental with perl v5.40 its use with a finally block still emitted a warning ... presumably because try and catch were added in perl v5.34, while finally was not added until perl v5.36 ... so I expect the finally block warning will finally disappear in perl v5.42. :-)

Perl Feature References Added Later

Recent Features:

• try catch finally (perldoc)
• Syntax::Keyword::Try on CPAN by Paul Evans - a try/catch/finally syntax for perl
• Feature::Compat::Try on CPAN by Paul Evans - make try/catch syntax available (if the new syntax is available this module simply enables the core feature equivalent to using it directly; on older versions of perl before such syntax is available, it is provided instead using Syntax::Keyword::Try)
• Try::Tiny on CPAN by Karen Etheridge - minimal try/catch with proper preservation of $@

• New built-in perl5.38 try/catch syntax by me (2023) - sample program using perl's new try/catch/finally syntax
• "try" partly experimental in v5.40 (2024) - update: thanks parv and hippo for replying to New built-in perl5.38 try/catch syntax and so further clarify that try/catch is no longer considered experimental in perl v5.40, but try/catch/finally is still deemed experimental

• perlclass (perldoc) - class, field, method
• Feature::Compat::Class on CPAN by Paul Evans - make class syntax available (a work-in-progress, like the underlying perlclass feature)
• Object::Pad on CPAN by Paul Evans - a simple syntax for lexical field-based objects

• Cor—An object system for the Perl core by Ovid (May 2020)
• The Corinna RFC for getting modern OO into the Perl core is taking shape by Ovid (Aug 2021)
• Corinna Update by Ovid (Nov 2021) - the Corinna code uses Object::Pad under the hood
• Corinna Project (github) - Bringing Modern OOP to the Perl Core (I believe this is the latest of Ovid's OO proposals)
• perlclasstut (github) - Corinna tutorial on Object-Oriented Programming in Perl via the class keyword
• The 'class' feature - this feature enables the class block syntax and other associated keywords which implement the "new" object system, previously codenamed "Corinna"

• What's New in Perl v5.40? Mohammad Sajid Anwar on perl.com (Jun 2024) : 1) new __CLASS__ keyword; 2) :reader attribute for field variables; 3) a space is permitted in the -M command-line option; 4) new ^^ logical xor operator; 5) try/catch feature is no longer experimental; 6) for iterating over multiple values at a time is no longer experimental

• builtin (perldoc) - Perl pragma to import built-in utility functions (introduced in perl v5.36)
• use builtin ':5.40' bundles true false weaken unweaken is_weak blessed refaddr reftype ceil floor is_tainted trim indexed
• Note: The overall builtin mechanism, as well as every individual function it provides, are currently experimental

• perlsub Signatures (perldoc)
• Signature::Attribute::Alias on CPAN by Paul Evans - make signature parameters that alias caller-provided values
• Signature::Attribute::Checked on CPAN by Paul Evans - apply value constraint checks to subroutine parameters
• Filter::signatures by Corion - very simplistic signatures for Perl < 5.20 (see Re: features and backwards compatibility)

• Sound from Scratch by haj (2024) - having fun playing with modern OO being brought into core Perl, especially recent stuff, such as the class feature (using Feature::Compat::Class, the signatures feature, and more)
• Using perlclass 'methods' by drudgesentinel (2024) - sample program using new OO perlclass
• Thoughts on new 'class' OO in upcoming perl by cavac (2023) - initial thoughts on upcoming perlclass
• Anyone migrated to the new 'class' way of OOP? by stevieb (2025)

Older Features:

• lexical sub vs subroutine reference by tomred (2024)
• Re: lexical sub vs subroutine reference by dave_the_m - Lexical subs (introduced in perl v5.26) are little more than syntactic sugar for storing anon subs in a lexical var, but with the calling syntax requiring a few less characters
• perlsub (perldoc, see Lexical Subroutines section) - you can declare a private subroutine with my or state

• Lexical::Sub on CPAN by Andrew Main (zefram) - subroutines without namespace pollution
• Sub::Lexical on CPAN by Dan Brook - implements lexically scoped subroutines
• Don't use named lexical subroutines by brian_d_foy (effective perl programming)

• state (perldoc)
• Persistent Private Variables (perldoc)
• Rosetta PGA-TRAM by me (2009) - example using persistent private state variables in Perl (introduced in perl v5.10)

• autodie (perldoc) - new core pragma added to perl v5.10.1

• Which pragmas are activated with a specific perl version? by adhrain (2018)
• perl5120delta (perldoc) - use v5.12 and above enables strictures as if you'd written use strict
• perl5360delta (perldoc) - use v5.36 and above also enables warnings as if you'd written use warnings

Basic Feature References:

• Perl 5 version history (wikipedia)
• Proposed Perl Changes (github)

• feature (perldoc) - Perl pragma to enable new features
• FEATURE BUNDLES (perldoc) - Feature bundles

• say feature - perl 5.10
• state feature - perl 5.10
• switch feature - perl 5.10: deprecated, removed in perl 5.42
• unicode_strings feature - perl 5.12
• unicode_eval and evalbytes features - perl 5.16
• current_sub feature - perl 5.16
• fc feature - perl 5.16
• lexical_subs feature - perl 5.26
• array_base feature - removed in perl 5.30
• postderef and postderef_qq features - perl 5.30
• signatures feature - perl 5.36
• refaliasing feature - perl 5.22 (still experimental)
• declared_refs feature - perl 5.26 (still experimental)
• ... Re^2: Passing argument by reference (for a scalar) by ikegami gives an example using refaliasing/declared_refs and compares to Data::Alias
• bitwise feature - perl 5.28
• isa feature - perl 5.36
• indirect feature - perl 5.32
• multidimensional feature - perl 5.34
• bareword_filehandles feature - perl 5.34
• try feature - perl 5.34
• builtin pragma - perl 5.36
• defer feature - perl 5.36
• extra_paired_delimiters feature - perl 5.36
• finally added to try feature - perl 5.36
• module_true feature - perl 5.38
• class feature - perl 5.38
• perl v5.40 feature bundle : bitwise current_sub evalbytes fc isa module_true postderef_qq say signatures state try unicode_eval unicode_strings

Feature switch Removal:

• feature switch is deprecated and scheduled to be removed in perl v5.42 - for (much) more detail search for Conway at Switch/smartmatch References and watch The Once and Future Perl (youtube 1.5 hr) by Damian Conway, TPRC 2024 Las Vegas

See Also

• The Perl and Raku Conference - Las Vegas, NV 2024 Playlists (youtube)
• Re^7: Meaning of XS object version (Package Manager Security References - example building Perl securely from source)
• Perl v5.42.0 is now available! by choroba

• modern perl 1.0 by cognominal (2021)
• Re: Obtaining old versions of Perl -- Perl 1.0 by me (2017)

👁️🍾👍🦟