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Changes for version 5.26.0

  • =head1 Notice
  • This release includes three updates with widespread effects:
  • =over 4
  • =item * C<"."> no longer in C<@INC>
  • For security reasons, the current directory (C<".">) is no longer included by default at the end of the module search path (C<@INC>). This may have widespread implications for the building, testing and installing of modules, and for the execution of scripts. See the section L<< Removal of the current directory (C<".">) from C<@INC> >> for the full details.
  • =item * C<do> may now warn
  • C<do> now gives a deprecation warning when it fails to load a file which it would have loaded had C<"."> been in C<@INC>.
  • =item * In regular expression patterns, a literal left brace C<"{"> should be escaped
  • See L</Unescaped literal C<"{"> characters in regular expression patterns are no longer permissible>.
  • =back
  • =head1 Core Enhancements
  • =head2 Lexical subroutines are no longer experimental
  • Using the C<lexical_subs> feature introduced in v5.18 no longer emits a warning. Existing code that disables the C<experimental::lexical_subs> warning category that the feature previously used will continue to work. The C<lexical_subs> feature has no effect; all Perl code can use lexical subroutines, regardless of what feature declarations are in scope.
  • =head2 Indented Here-documents
  • This adds a new modifier C<"~"> to here-docs that tells the parser that it should look for C</^\s*$DELIM\n/> as the closing delimiter.
  • These syntaxes are all supported:
    • <<~EOF; <<~\EOF; <<~'EOF'; <<~"EOF"; <<~`EOF`; <<~ 'EOF'; <<~ "EOF"; <<~ `EOF`;
  • The C<"~"> modifier will strip, from each line in the here-doc, the same whitespace that appears before the delimiter.
  • Newlines will be copied as-is, and lines that don't include the proper beginning whitespace will cause perl to croak.
  • For example:
    • if (1) { print <<~EOF; Hello there EOF }
  • prints "Hello there\n" with no leading whitespace.
  • =head2 New regular expression modifier C</xx>
  • Specifying two C<"x"> characters to modify a regular expression pattern does everything that a single one does, but additionally TAB and SPACE characters within a bracketed character class are generally ignored and can be added to improve readability, like S<C</[ ^ A-Z d-f p-x ]/xx>>. Details are at L<perlre/E<sol>x and E<sol>xx>.
  • =head2 C<@{^CAPTURE}>, C<%{^CAPTURE}>, and C<%{^CAPTURE_ALL}>
  • C<@{^CAPTURE}> exposes the capture buffers of the last match as an array. So C<$1> is C<${^CAPTURE}[0]>. This is a more efficient equivalent to code like C<substr($matched_string,$-[0],$+[0]-$-[0])>, and you don't have to keep track of the C<$matched_string> either. This variable has no single character equivalent. Note that, like the other regex magic variables, the contents of this variable is dynamic; if you wish to store it beyond the lifetime of the match you must copy it to another array.
  • C<%{^CAPTURE}> is equivalent to C<%+> (I<i.e.>, named captures). Other than being more self-documenting there is no difference between the two forms.
  • C<%{^CAPTURE_ALL}> is equivalent to C<%-> (I<i.e.>, all named captures). Other than being more self-documenting there is no difference between the two forms.
  • =head2 Declaring a reference to a variable
  • As an experimental feature, Perl now allows the referencing operator to come after L<C<my()>|perlfunc/my>, L<C<state()>|perlfunc/state>, L<C<our()>|perlfunc/our>, or L<C<local()>|perlfunc/local>. This syntax must be enabled with C<use feature 'declared_refs'>. It is experimental, and will warn by default unless C<no warnings 'experimental::refaliasing'> is in effect. It is intended mainly for use in assignments to references. For example:
    • use experimental 'refaliasing', 'declared_refs'; my \$a = \$b;
  • See L<perlref/Assigning to References> for more details.
  • =head2 Unicode 9.0 is now supported
  • A list of changes is at L<http://www.unicode.org/versions/Unicode9.0.0/>. Modules that are shipped with core Perl but not maintained by p5p do not necessarily support Unicode 9.0. L<Unicode::Normalize> does work on 9.0.
  • =head2 Use of C<\p{I<script>}> uses the improved Script_Extensions property
  • Unicode 6.0 introduced an improved form of the Script (C<sc>) property, and called it Script_Extensions (C<scx>). Perl now uses this improved version when a property is specified as just C<\p{I<script>}>. This should make programs more accurate when determining if a character is used in a given script, but there is a slight chance of breakage for programs that very specifically needed the old behavior. The meaning of compound forms, like C<\p{sc=I<script>}> are unchanged. See L<perlunicode/Scripts>.
  • =head2 Perl can now do default collation in UTF-8 locales on platforms that support it
  • Some platforms natively do a reasonable job of collating and sorting in UTF-8 locales. Perl now works with those. For portability and full control, L<Unicode::Collate> is still recommended, but now you may not need to do anything special to get good-enough results, depending on your application. See L<perllocale/Category C<LC_COLLATE>: Collation: Text Comparisons and Sorting>.
  • =head2 Better locale collation of strings containing embedded C<NUL> characters
  • In locales that have multi-level character weights, C<NUL>s are now ignored at the higher priority ones. There are still some gotchas in some strings, though. See L<perllocale/Collation of strings containing embedded C<NUL> characters>.
  • =head2 C<CORE> subroutines for hash and array functions callable via reference
  • The hash and array functions in the C<CORE> namespace (C<keys>, C<each>, C<values>, C<push>, C<pop>, C<shift>, C<unshift> and C<splice>) can now be called with ampersand syntax (C<&CORE::keys(\%hash>) and via reference (C<< my $k = \&CORE::keys; $k-E<gt>(\%hash) >>). Previously they could only be used when inlined.
  • =head2 New Hash Function For 64-bit Builds
  • We have switched to a hybrid hash function to better balance performance for short and long keys.
  • For short keys, 16 bytes and under, we use an optimised variant of One At A Time Hard, and for longer keys we use Siphash 1-3. For very long keys this is a big improvement in performance. For shorter keys there is a modest improvement.
  • =head1 Security
  • =head2 Removal of the current directory (C<".">) from C<@INC>
  • The perl binary includes a default set of paths in C<@INC>. Historically it has also included the current directory (C<".">) as the final entry, unless run with taint mode enabled (C<perl -T>). While convenient, this has security implications: for example, where a script attempts to load an optional module when its current directory is untrusted (such as F</tmp>), it could load and execute code from under that directory.
  • Starting with v5.26, C<"."> is always removed by default, not just under tainting. This has major implications for installing modules and executing scripts.
  • The following new features have been added to help ameliorate these issues.
  • =over
  • =item * F<Configure -Udefault_inc_excludes_dot>
  • There is a new F<Configure> option, C<default_inc_excludes_dot> (enabled by default) which builds a perl executable without C<".">; unsetting this option using C<-U> reverts perl to the old behaviour. This may fix your path issues but will reintroduce all the security concerns, so don't build a perl executable like this unless you're I<really> confident that such issues are not a concern in your environment.
  • =item * C<PERL_USE_UNSAFE_INC>
  • There is a new environment variable recognised by the perl interpreter. If this variable has the value 1 when the perl interpreter starts up, then C<"."> will be automatically appended to C<@INC> (except under tainting).
  • This allows you restore the old perl interpreter behaviour on a case-by-case basis. But note that this is intended to be a temporary crutch, and this feature will likely be removed in some future perl version. It is currently set by the C<cpan> utility and C<Test::Harness> to ease installation of CPAN modules which have not been updated to handle the lack of dot. Once again, don't use this unless you are sure that this will not reintroduce any security concerns.
  • =item * A new deprecation warning issued by C<do>.
  • While it is well-known that C<use> and C<require> use C<@INC> to search for the file to load, many people don't realise that C<do "file"> also searches C<@INC> if the file is a relative path. With the removal of C<".">, a simple C<do "file.pl"> will fail to read in and execute C<file.pl> from the current directory. Since this is commonly expected behaviour, a new deprecation warning is now issued whenever C<do> fails to load a file which it otherwise would have found if a dot had been in C<@INC>.
  • =back
  • Here are some things script and module authors may need to do to make their software work in the new regime.
  • =over
  • =item * Script authors
  • If the issue is within your own code (rather than within included modules), then you have two main options. Firstly, if you are confident that your script will only be run within a trusted directory (under which you expect to find trusted files and modules), then add C<"."> back into the path; I<e.g.>:
    • BEGIN { my $dir = "/some/trusted/directory"; chdir $dir or die "Can't chdir to $dir: $!\n";
      • safe now push @INC, '.';
    • }
    • use "Foo::Bar"; # may load /some/trusted/directory/Foo/Bar.pm do "config.pl"; # may load /some/trusted/directory/config.pl
  • On the other hand, if your script is intended to be run from within untrusted directories (such as F</tmp>), then your script suddenly failing to load files may be indicative of a security issue. You most likely want to replace any relative paths with full paths; for example,
    • do "foo_config.pl"
  • might become
    • do "$ENV{HOME}/foo_config.pl"
  • If you are absolutely certain that you want your script to load and execute a file from the current directory, then use a C<./> prefix; for example:
    • do "./foo_config.pl"
  • =item * Installing and using CPAN modules
  • If you install a CPAN module using an automatic tool like C<cpan>, then this tool will itself set the C<PERL_USE_UNSAFE_INC> environment variable while building and testing the module, which may be sufficient to install a distribution which hasn't been updated to be dot-aware. If you want to install such a module manually, then you'll need to replace the traditional invocation:
    • perl Makefile.PL && make && make test && make install
  • with something like
    • (export PERL_USE_UNSAFE_INC=1; \ perl Makefile.PL && make && make test && make install)
  • Note that this only helps build and install an unfixed module. It's possible for the tests to pass (since they were run under C<PERL_USE_UNSAFE_INC=1>), but for the module itself to fail to perform correctly in production. In this case, you may have to temporarily modify your script until a fixed version of the module is released. For example:
    • use Foo::Bar; { local @INC = (@INC, '.');
      • assuming read_config() needs '.' in @INC $config = Foo::Bar->read_config();
    • }
  • This is only rarely expected to be necessary. Again, if doing this, assess the resultant risks first.
  • =item * Module Authors
  • If you maintain a CPAN distribution, it may need updating to run in a dotless environment. Although C<cpan> and other such tools will currently set the C<PERL_USE_UNSAFE_INC> during module build, this is a temporary workaround for the set of modules which rely on C<"."> being in C<@INC> for installation and testing, and this may mask deeper issues. It could result in a module which passes tests and installs, but which fails at run time.
  • During build, test, and install, it will normally be the case that any perl processes will be executing directly within the root directory of the untarred distribution, or a known subdirectory of that, such as F<t/>. It may well be that F<Makefile.PL> or F<t/foo.t> will attempt to include local modules and configuration files using their direct relative filenames, which will now fail.
  • However, as described above, automatic tools like F<cpan> will (for now) set the C<PERL_USE_UNSAFE_INC> environment variable, which introduces dot during a build.
  • This makes it likely that your existing build and test code will work, but this may mask issues with your code which only manifest when used after install. It is prudent to try and run your build process with that variable explicitly disabled:
    • (export PERL_USE_UNSAFE_INC=0; \ perl Makefile.PL && make && make test && make install)
  • This is more likely to show up any potential problems with your module's build process, or even with the module itself. Fixing such issues will ensure both that your module can again be installed manually, and that it will still build once the C<PERL_USE_UNSAFE_INC> crutch goes away.
  • When fixing issues in tests due to the removal of dot from C<@INC>, reinsertion of dot into C<@INC> should be performed with caution, for this too may suppress real errors in your runtime code. You are encouraged wherever possible to apply the aforementioned approaches with explicit absolute/relative paths, or to relocate your needed files into a subdirectory and insert that subdirectory into C<@INC> instead.
  • If your runtime code has problems under the dotless C<@INC>, then the comments above on how to fix for script authors will mostly apply here too. Bear in mind though that it is considered bad form for a module to globally add a dot to C<@INC>, since it introduces both a security risk and hides issues of accidentally requiring dot in C<@INC>, as explained above.
  • =back
  • =head2 Escaped colons and relative paths in PATH
  • On Unix systems, Perl treats any relative paths in the C<PATH> environment variable as tainted when starting a new process. Previously, it was allowing a backslash to escape a colon (unlike the OS), consequently allowing relative paths to be considered safe if the PATH was set to something like C</\:.>. The check has been fixed to treat C<"."> as tainted in that example.
  • =head2 New C<-Di> switch is now required for PerlIO debugging output
  • This is used for debugging of code within PerlIO to avoid recursive calls. Previously this output would be sent to the file specified by the C<PERLIO_DEBUG> environment variable if perl wasn't running setuid and the C<-T> or C<-t> switches hadn't been parsed yet.
  • If perl performed output at a point where it hadn't yet parsed its switches this could result in perl creating or overwriting the file named by C<PERLIO_DEBUG> even when the C<-T> switch had been supplied.
  • Perl now requires the C<-Di> switch to be present before it will produce PerlIO debugging output. By default this is written to C<stderr>, but can optionally be redirected to a file by setting the C<PERLIO_DEBUG> environment variable.
  • If perl is running setuid or the C<-T> switch was supplied, C<PERLIO_DEBUG> is ignored and the debugging output is sent to C<stderr> as for any other C<-D> switch.
  • =head1 Incompatible Changes
  • =head2 Unescaped literal C<"{"> characters in regular expression patterns are no longer permissible
  • You have to now say something like C<"\{"> or C<"[{]"> to specify to match a LEFT CURLY BRACKET; otherwise, it is a fatal pattern compilation error. This change will allow future extensions to the language.
  • These have been deprecated since v5.16, with a deprecation message raised for some uses starting in v5.22. Unfortunately, the code added to raise the message was buggy and failed to warn in some cases where it should have. Therefore, enforcement of this ban for these cases is deferred until Perl 5.30, but the code has been fixed to raise a default-on deprecation message for them in the meantime.
  • Some uses of literal C<"{"> occur in contexts where we do not foresee the meaning ever being anything but the literal, such as the very first character in the pattern, or after a C<"|"> meaning alternation. Thus
    • qr/{fee|{fie/
  • matches either of the strings C<{fee> or C<{fie>. To avoid forcing unnecessary code changes, these uses do not need to be escaped, and no warning is raised about them, and there are no current plans to change this.
  • But it is always correct to escape C<"{">, and the simple rule to remember is to always do so.
  • See L<Unescaped left brace in regex is illegal here|perldiag/Unescaped left brace in regex is illegal here in regex; marked by S<E<lt>-- HERE> in mE<sol>%sE<sol>>.
  • =head2 C<scalar(%hash)> return signature changed
  • The value returned for C<scalar(%hash)> will no longer show information about the buckets allocated in the hash. It will simply return the count of used keys. It is thus equivalent to C<0+keys(%hash)>.
  • A form of backward compatibility is provided via L<C<Hash::Util::bucket_ratio()>|Hash::Util/bucket_ratio> which provides the same behavior as C<scalar(%hash)> provided in Perl 5.24 and earlier.
  • =head2 C<keys> returned from an lvalue subroutine
  • C<keys> returned from an lvalue subroutine can no longer be assigned to in list context.
    • sub foo : lvalue { keys(%INC) } (foo) = 3; # death sub bar : lvalue { keys(@_) } (bar) = 3; # also an error
  • This makes the lvalue sub case consistent with C<(keys %hash) = ...> and C<(keys @_) = ...>, which are also errors. L<[perl #128187]|https://rt.perl.org/Public/Bug/Display.html?id=128187>
  • =head2 The C<${^ENCODING}> facility has been removed
  • The special behaviour associated with assigning a value to this variable has been removed. As a consequence, the L<encoding> pragma's default mode is no longer supported. If you still need to write your source code in encodings other than UTF-8, use a source filter such as L<Filter::Encoding> on CPAN or L<encoding>'s C<Filter> option.
  • =head2 C<POSIX::tmpnam()> has been removed
  • The fundamentally unsafe C<tmpnam()> interface was deprecated in Perl 5.22 and has now been removed. In its place, you can use, for example, the L<File::Temp> interfaces.
  • =head2 require ::Foo::Bar is now illegal.
  • Formerly, C<require ::Foo::Bar> would try to read F</Foo/Bar.pm>. Now any bareword require which starts with a double colon dies instead.
  • =head2 Literal control character variable names are no longer permissible
  • A variable name may no longer contain a literal control character under any circumstances. These previously were allowed in single-character names on ASCII platforms, but have been deprecated there since Perl

Documentation

README for the Porting/ directory in the Perl 5 core distribution.
Compare the performance of perl code snippets across multiple perls.
use git bisect to pinpoint changes
Check that all the URLs in the Perl source are valid
Check source code for ANSI-C violations
list of Perl release epigraphs
expand C macros using the C preprocessor
Annotate commits for perldelta
How to write a perldelta
Notes on handling the Perl Patch Pumpkin And Porting Perl
Releasing a new version of perl 5.x
Perl 5 release schedule
Sort warning and error messages in perldiag.pod
Perl TO-DO list
A post processor for make test.valgrind
autogenerated documentation for the perl public API
access Perl configuration information
lib
manipulate @INC at compile time
Dynamically load C libraries into Perl code
System errno constants
Group Perl's functions a la perlfunc.pod
Test Pod::Functions
convert .pod files to .html files
Test Pod::Html::anchorify()
the
Test HTML cross reference links
Test --htmldir feature
Test --htmldir feature
Test --htmldir feature
Test --htmldir feature
Test --htmldir feature
Test HTML links
Plain Old Documentation: format specification and notes
Perl predefined variables
converts a collection of POD pages to HTML format.
Namespace for Perl's core routines
Reserved special namespace for internals related functions
The tests for Pod::InputObjects
Tests for Pod::Select.
Tests for Pod::Usage
the perl debugger
make patchnum
distribute ppport.h among extensions
The Perl 5 language interpreter
what's new for perl5.004
what's new for perl5.005
what is new for perl 5.10.0
what is new for perl v5.10.1
what is new for perl v5.12.0
what is new for perl v5.12.1
what is new for perl v5.12.2
what is new for perl v5.12.3
what is new for perl v5.12.4
what is new for perl v5.12.5
what is new for perl v5.14.0
what is new for perl v5.14.1
what is new for perl v5.14.2
what is new for perl v5.14.3
what is new for perl v5.14.4
what is new for perl v5.16.0
what is new for perl v5.16.1
what is new for perl v5.16.2
what is new for perl v5.16.3
what is new for perl v5.18.0
what is new for perl v5.18.1
what is new for perl v5.18.2
what is new for perl v5.18.4
what is new for perl v5.20.0
what is new for perl v5.20.1
what is new for perl v5.20.2
what is new for perl v5.20.3
what is new for perl v5.22.0
what is new for perl v5.22.1
what is new for perl v5.22.2
what is new for perl v5.22.3
what is new for perl v5.24.0
what is new for perl v5.24.1
what's new for perl v5.6.1
what's new for perl v5.6.0
what is new for perl v5.8.1
what is new for perl v5.8.2
what is new for perl v5.8.3
what is new for perl v5.8.4
what is new for perl v5.8.5
what is new for perl v5.8.6
what is new for perl v5.8.7
what is new for perl v5.8.8
what is new for perl v5.8.9
what is new for perl v5.8.0
perl's IO abstraction interface.
the Perl Artistic License
Books about and related to Perl
Links to information on object-oriented programming in Perl
Links to information on object-oriented programming in Perl
Perl calling conventions from C
Perl 5 Cheat Sheet
Internal replacements for standard C library functions
a brief overview of the Perl community
Perl data types
Perl DBM Filters
Guts of Perl debugging
Perl debugging tutorial
Perl debugging
what is new for perl v5.26.0
list Perl deprecations
various Perl diagnostics
Perl Data Structures Cookbook
Perl's support for DTrace
Considerations for running Perl on EBCDIC platforms
how to embed perl in your C program
A listing of experimental features in Perl
Source Filters
Perl's fork() emulation
Perl formats
Perl builtin functions
Detailed information about git and the Perl repository
the GNU General Public License, version 1
Introduction to the Perl API
How to hack on Perl
Tips for Perl core C code hacking
Walk through the creation of a simple C code patch
the Perl history records
An overview of the Perl interpreter
a brief introduction and overview of Perl
C API for Perl's implementation of IO in Layers.
Perl interprocess communication (signals, fifos, pipes, safe subprocesses, sockets, and semaphores)
Perl Lexical Warnings
Perl locale handling (internationalization and localization)
Manipulating Arrays of Arrays in Perl
Perl modules (packages and symbol tables)
Installing CPAN Modules
constructing new Perl modules and finding existing ones
Perl module style guide
Perl method resolution plugin interface
preparing a new module for distribution
semantics of numbers and numeric operations in Perl
Perl object reference
Object-Oriented Programming in Perl Tutorial
Perl operators and precedence
simple recipes for opening files and pipes in Perl
tutorial on pack and unpack
Perl Performance and Optimization Techniques
the Plain Old Documentation format
Plain Old Documentation: format specification and notes
Perl POD style guide
Various and sundry policies and commitments related to the Perl core
Writing portable Perl
how to write a user pragma
Perl regular expressions
Perl regular expression plugin interface
Perl Regular Expression Backslash Sequences and Escapes
Perl Regular Expression Character Classes
Perl references and nested data structures
Mark's very short tutorial about references
Description of the Perl regular expression engine.
Links to current information on the Perl source repository
Perl regular expressions quick start
Perl Regular Expressions Reference
Perl regular expressions tutorial
how to execute the Perl interpreter
Perl security
A guide to the Perl source tree
Perl style guide
Perl subroutines
Perl syntax
Tutorial on threads in Perl
how to hide an object class in a simple variable
Link to the Perl to-do list
Links to information on object-oriented programming in Perl
Links to information on object-oriented programming in Perl
Perl traps for the unwary
Unicode support in Perl
cookbookish examples of handling Unicode in Perl
Perl Unicode FAQ
Perl Unicode introduction
Perl Unicode Tutorial
utilities packaged with the Perl distribution
Perl predefined variables
VMS-specific documentation for Perl
Perl pragma to enable new features
Generate C macros that match character classes efficiently
Perl pragma to control optional warnings
a C++ base class encapsulating a Perl interpreter in Symbian
a C++ utility class for Perl/Symbian
convert .h C header files to .ph Perl header files
convert .h C header files to Perl extensions
configure libnet
how to submit bug reports on Perl
Perl Installation Verification Procedure
Rough tool to translate Perl4 .pl files to Perl5 .pm modules.

Modules

functions for dealing with RFC3066-style language tags
detect the user's language preferences
tags and names for human languages
IO
load various IO modules
supply object methods for directory handles
supply object methods for filehandles
supply object methods for I/O handles
supply object methods for pipes
Object interface to system poll call
supply seek based methods for I/O objects
OO interface to the select system call
Object interface to socket communications
Object interface for AF_INET domain sockets
Object interface for AF_UNIX domain sockets
Perl extension for ARexx support
Perl extension for low level amiga support
B
The Perl Compiler Backend
Walk Perl syntax tree, printing concise info about ops
Show lexical variables used in functions or files
Walk Perl syntax tree, printing terse info about ops
Generates cross reference reports for Perl programs
O
Generic interface to Perl Compiler backends
check optrees as rendered by B::Concise
A data debugging tool for the XS programmer
write the C code for miniperlmain.c and perlmain.c
load the C Fcntl.h defines
DOS like globbing and then some
Traverse a directory tree.
Perl extension for BSD glob routine
keep more files open than the system permits
Perl5 access to the gdbm library.
Support for Inside-Out Classes
A selection of general-utility hash subroutines
query locale information
open a process for both reading and writing using open2()
open a process for reading, writing, and error handling using open3()
Tied access to ndbm files
Tied access to odbm files
Disable named opcodes when compiling perl code
ops
Perl pragma to restrict unsafe operations when compiling
Perl interface to IEEE Std 1003.1
encoding layer
Memory mapped IO
in-memory IO, scalar IO
Helper class for PerlIO layers implemented in perl
module to convert pod files to HTML
Tied access to sdbm files
Try every conceivable way to get hostname
Named regexp capture buffers
add data to hash when needed
Perl extension to manipulate DCL symbols
convert between VMS and Unix file specification syntax
standard I/O functions via VMS extensions
Win32 CORE function stubs
Test the perl C API
module to test the XS typemaps distributed with perl
Set indexing base via $[
get/set subroutine or variable attributes
mro
Method Resolution Order
re
Perl pragma to alter regular expression behaviour
Interfaces to some Haiku API Functions
provide framework for multiple DBMs
Perl compiler backend to produce perl code
OP op_private flag definitions
benchmark running times of Perl code
declare struct-like datatypes as Perl classes
hash lookup of which core extensions were built.
DB
programmatic interface to the Perl debugging API
Filter DBM keys/values
filter for DBM_Filter
filter for DBM_Filter
filter for DBM_Filter
filter for DBM_Filter
filter for DBM_Filter
supply object methods for directory handles
use nice English (or awk) names for ugly punctuation variables
Utilities for embedding Perl in C/C++ applications
keep sets of symbol names palatable to the VMS linker
Parse file paths into directory, filename and suffix.
Compare files or filehandles
Copy files or filehandles
by-name interface to Perl's built-in stat() functions
supply object methods for filehandles
Locate directory of original perl script
Process single-character switches with switch clustering
by-name interface to Perl's built-in gethost*() functions
by-name interface to Perl's built-in getnet*() functions
by-name interface to Perl's built-in getproto*() functions
by-name interface to Perl's built-in getserv*() functions
On demand loader for PerlIO layers and root of PerlIO::* name space
save and restore selected file handle
manipulate Perl symbols and their names
Manipulate threads in Perl (for old code only)
base class for tied arrays
base class definitions for tied handles
base class definitions for tied handles
Fixed-table-size, fixed-key-length hashing
by-name interface to Perl's built-in gmtime() function
by-name interface to Perl's built-in localtime() function
internal object used by Time::gmtime and Time::localtime
base class for ALL classes (blessed references)
Unicode character database
by-name interface to Perl's built-in getgr*() functions
by-name interface to Perl's built-in getpw*() functions
Use MakeMaker's uninstalled version of a package
Perl pragma to expose the individual bytes of characters
access to Unicode character names and named character sequences; also define character names
Perl pragma for deprecating the core version of a module
Perl pragma to enable new features
Perl pragma to control the filetest permission operators
Perl pragma to use integer arithmetic instead of floating point
perl pragma to request less of something
Perl pragma to use or avoid POSIX locales for built-in operations
perl pragma to set default PerlIO layers for input and output
Package for overloading Perl operations
perl pragma to lexically control overloading
Perl pragma to enable simple signal handling
perl pragma to control sort() behaviour
Perl pragma to restrict unsafe constructs
Perl pragma to predeclare sub names
Perl pragma to enable/disable UTF-8 (or UTF-EBCDIC) in source code
Perl pragma to predeclare global variable names
Perl pragma to control VMS-specific language features
Perl pragma to control optional warnings
warnings import function
Perl access to extended attributes.
Perl extension for access to OS/2 setting database.
exports constants for system() call, and process control on OS2.
access to DLLs with REXX calling convention.
access to DLLs with REXX calling convention and REXX runtime.

Provides

in ext/Amiga-ARexx/ARexx.pm
in ext/B/B.pm
in lib/Class/Struct.pm
in symbian/ext/Moped/Msg/Msg.pm
in os2/OS2/OS2-REXX/DLL/DLL.pm
in os2/OS2/OS2-PrfDB/PrfDB.pm
in os2/OS2/OS2-PrfDB/PrfDB.pm
in os2/OS2/OS2-REXX/REXX.pm
in os2/OS2/OS2-REXX/REXX.pm
in os2/OS2/OS2-REXX/REXX.pm
in os2/OS2/OS2-Process/Process.pm
in ext/POSIX/lib/POSIX.pm
in ext/POSIX/lib/POSIX.pm
in ext/POSIX/lib/POSIX.pm
in ext/Pod-Html/lib/Pod/Html.pm
in ext/File-Find/t/lib/Testing.pm
in lib/Tie/Hash.pm
in lib/DBM_Filter.pm
in lib/Tie/Hash.pm
in lib/Tie/Scalar.pm
in lib/Tie/Array.pm
in lib/Tie/Hash.pm
in lib/Tie/Scalar.pm
in ext/VMS-Stdio/Stdio.pm
in lib/diagnostics.pm
in lib/overload/numbers.pm
in ext/XS-APItest/t/BHK.pm
in ext/XS-APItest/t/Markers.pm