perlwin32(1) - Man pages

PERLWIN32(1) Perl Programmers Reference Guide PERLWIN32(1)

NAME
perlwin32 - Perl under Windows

SYNOPSIS
These are instructions for building Perl under Windows 7 and later.

DESCRIPTION
Before you start, you should glance through the README file found in the
top-level directory to which the Perl distribution was extracted. Make
sure you read and understand the terms under which this software is
being distributed.

Also make sure you read "BUGS AND CAVEATS" below for the known
limitations of this port.

The INSTALL file in the perl top-level has much information that is only
relevant to people building Perl on Unix-like systems. In particular,
you can safely ignore any information that talks about "Configure".

You may also want to look at one other option for building a perl that
will work on Windows: the README.cygwin file, which give a different set
of rules to build a perl for Windows. This method will probably enable
you to build a more Unix-compatible perl, but you will also need to
download and use various other build-time and run-time support software
described in that file.

This set of instructions is meant to describe a so-called "native" port
of Perl to the Windows platform. This includes both 32-bit and 64-bit
Windows operating systems. The resulting Perl requires no additional
software to run (other than what came with your operating system).
Currently, this port is capable of using one of the following compilers
on the Intel x86 and x86_64 architectures:

Microsoft Visual C++ Visual C++ 2015 (version 14.0) or later
Intel C++ Compiler (experimental)
Gcc by mingw.org gcc version 3.4.5-5.3.0
Gcc by mingw-w64.org gcc version 4.4.3 or later

Note that the last two of these are actually competing projects both
delivering complete gcc toolchain for MS Windows:

<https://osdn.net/projects/mingw/>
Delivers gcc toolchain building 32-bit executables (which can be
used both 32 and 64 bit Windows platforms)

<https://mingw-w64.org>
Delivers gcc toolchain targeting both 64-bit Windows and 32-bit
Windows platforms (despite the project name "mingw-w64" they are not
only 64-bit oriented). They deliver the native gcc compilers and
cross-compilers that are also supported by perl's makefile.

The Microsoft Visual C++ compilers are also now being given away free.
They are available as "Visual C++ 2015-2022 Community Edition" and are
the same compilers that ship with "Visual C++ 2015-2022 Professional".

The MinGW64 compiler is available at <https://mingw-w64.org>. The
latter is actually a cross-compiler targeting Win64. There's also a
trimmed down compiler (no java, or gfortran) suitable for building perl
available at: <https://strawberryperl.com/package/kmx/64_gcctoolchain/>

NOTE: If you're using a 32-bit compiler to build perl on a 64-bit
Windows operating system, then you should set the WIN64 environment
variable to "undef". Also, the trimmed down compiler only passes tests
when USE_ITHREADS *= define (as opposed to undef) and when the CFG *=
Debug line is commented out.

This port fully supports MakeMaker (the set of modules that is used to
build extensions to perl). Therefore, you should be able to build and
install most extensions found in the CPAN sites. See "Usage Hints for
Perl on Windows" below for general hints about this.

Setting Up Perl on Windows
Make
You need a "make" program to build the sources. If you are using
Visual C++, you can use nmake supplied with Visual C++. You may
also use gmake instead of nmake. Builds using gcc need gmake. nmake
is not supported for gcc builds. Parallel building is only
supported with gmake, not nmake.

Command Shell
Use the default "cmd" shell that comes with Windows. Some versions
of the popular 4DOS/NT shell have incompatibilities that may cause
you trouble. If the build fails under that shell, try building
again with the cmd shell.

Make sure the path to the build directory does not contain spaces.
The build usually works in this circumstance, but some tests will
fail.

Microsoft Visual C++
The nmake that comes with Visual C++ will suffice for building.
Visual C++ requires that certain things be set up in the console
before Visual C++ will successfully run. To make a console box be
able to run the C compiler, you will need to beforehand, run
"vcvarsall.bat x86" to compile for x86-32 and for x86-64
"vcvarsall.bat amd64". On a typical install of a Microsoft C++
compiler product, these batch files will already be in your "PATH"
environment variable so you may just type them without an absolute
path into your console. If you need to find the absolute path to the
batch file, it is usually found somewhere like C:\Program Files
(x86)\Microsoft Visual Studio 14.0\VC. With some newer Microsoft C
products (released after ~2004), the installer will put a shortcut
in the start menu to launch a new console window with the console
already set up for your target architecture (x86-32 or x86-64 or
IA64). With the newer compilers, you may also use the older batch
files if you choose so.

Microsoft Visual C++ 2015-2022 Community Edition
These free versions of Visual C++ 2015-2022 Professional contain the
same compilers and linkers that ship with the full versions, and
also contain everything necessary to build Perl.

These packages can be downloaded from
<https://visualstudio.microsoft.com/>.

Install Visual C++ 2015-2022 Community, then setup your environment
using, e.g.

C:\Program Files\Microsoft Visual Studio
14.0\Common7\Tools\vsvars32.bat

(assuming the default installation location was chosen).

Perl should now build using the win32/Makefile. You will need to
edit that file to set "CCTYPE" to one of "MSVC140"-"MSVC143" first.

Microsoft C++ Build Tools
There's also a standalone (IDE-less) version of the build tools
mentioned above containing the MSVC compiler available for download
from <https://visualstudio.microsoft.com/visual-cpp-build-tools/>.

This is also referred to as Build Tools for Visual Studio.

GCC Perl can be compiled with gcc from MinGW (version 3.4.5 or later) or
from MinGW64 (version 4.4.3 or later). It can be downloaded here:

<https://osdn.net/projects/mingw/> <https://www.mingw-w64.org/>

You also need gmake. Usually it comes with MinGW but its executable
may have a different name, such as mingw32-make.exe.

Note that the MinGW build currently fails with version 6.3.0 or
later.

Note also that the C++ mode build currently fails with MinGW 3.4.5
and 4.7.2 or later, and with MinGW64 64-bit 6.3.0 or later.

Intel C++ Compiler
Experimental support for using Intel C++ Compiler has been added.
Edit win32/Makefile and pick the correct "CCTYPE" for the Visual C
that Intel C was installed into. Also uncomment "__ICC" to enable
Intel C on Visual C support. To set up the build environment, from
the Start Menu run IA-32 Visual Studio 20__ mode or Intel 64 Visual
Studio 20__ mode as appropriate. Then run "nmake" as usual in that
prompt box.

Only Intel C++ Compiler v12.1 has been tested. Other versions
probably will work. Using Intel C++ Compiler instead of Visual C has
the benefit of C99 compatibility which is needed by some CPAN XS
modules, while maintaining compatibility with Visual C object code
and Visual C debugging infrastructure unlike GCC.

Building
• Make sure you are in the win32 subdirectory under the perl toplevel.
This directory contains a Makefile that will work with versions of
"nmake" that come with Visual C++, and a GNU make GNUmakefile that
will work for all supported compilers. The defaults in the "gmake"
makefile are set up to build with MinGW/gcc.

• Edit the GNUmakefile (or Makefile, if you're using nmake) and change
the values of INST_DRV and "INST_TOP". You can also enable various
build flags. These are explained in the makefiles.

Note that it is generally not a good idea to try to build a "perl"
with "INST_DRV" and "INST_TOP" set to a path that already exists
from a previous build. In particular, this may cause problems with
the lib/ExtUtils/t/Embed.t test, which attempts to build a test
program and may end up building against the installed "perl"'s
lib/CORE directory rather than the one being tested.

You will have to make sure that "CCTYPE" is set correctly and that
"CCHOME" points to wherever you installed your compiler. For GCC
this should be the directory that contains the bin, include and lib
directories.

If building with the cross-compiler provided by mingw-w64.org you'll
need to uncomment the line that sets "GCCCROSS" in the GNUmakefile.
Do this only if it's the cross-compiler, ie. only if the bin folder
doesn't contain a gcc.exe. (The cross-compiler does not provide a
gcc.exe, g++.exe, ar.exe, etc. Instead, all of these executables are
prefixed with "x86_64-w64-mingw32-".)

The default value for "CCHOME" in the makefiles for Visual C++ may
not be correct for some versions. Make sure the default exists and
is valid.

If you want build some core extensions statically into "perl"'s DLL,
specify them in the "STATIC_EXT" macro.

Be sure to read the instructions near the top of the makefiles
carefully.

• Type "gmake" (or "nmake" if you are using that version of "make").

This should build everything. Specifically, it will create
perl.exe, perl540.dll at the perl toplevel, and various other
extension DLL's under the lib\auto directory. If the build fails
for any reason, make sure you have done the previous steps
correctly.

To try "gmake"'s parallel mode, type "gmake -j2" where 2 is the
maximum number of parallel jobs you want to run. A number of things
in the build process will run in parallel, but there are
serialization points where you will see just 1 CPU maxed out. This
is normal.

If you are advanced enough with building C code, here is a
suggestion to speed up building "perl", and the later "make test".
Try to keep your "PATH" environment variable with the least number
of folders possible (remember to keep your C compiler's folders
there). C:\WINDOWS\system32 or C:\WINNT\system32 depending on your
OS version should be first folder in "PATH", since "cmd.exe" is the
most commonly launched program during the build and later testing.

Testing Perl on Windows
Type "gmake test" (or "nmake test"). This will run most of the tests
from the testsuite (many tests will be skipped).

There should be no test failures.

If you build with Visual C++ 2015 or later then
ext/XS-APItest/t/locale.t may crash (after all its tests have passed).
This is due to a regression in the Universal CRT introduced in the
Windows 10 April 2018 Update, and will be fixed in the May 2019 Update,
as explained here:
<https://developercommunity.visualstudio.com/content/problem/519486/setlocalelc-numeric-iso-latin-16-fails-then-succee.html>.

If you build with certain versions (e.g. 4.8.1) of gcc from mingw then
ext/POSIX/t/time.t may fail test 17 due to a known bug in those gcc
builds: see <https://sourceforge.net/p/mingw/bugs/2152/>.

Some test failures may occur if you use a command shell other than the
native "cmd.exe", or if you are building from a path that contains
spaces. So don't do that.

If you are running the tests from a emacs shell window, you may see
failures in op/stat.t. Run "gmake test-notty" in that case.

Furthermore, you should make sure that during "make test" you do not
have any GNU tool packages in your path: some toolkits like Unixutils
include some tools ("type" for instance) which override the Windows ones
and makes tests fail. Remove them from your path while testing to avoid
these errors.

To see the output of specific failing tests run the harness from the t
directory:

# assuming you're starting from the win32 directory
cd ..\win32
.\perl harness <list of tests>

Please report any other failures as described under "BUGS AND CAVEATS".

Installation of Perl on Windows
Type "gmake install" ("nmake install"). This will put the newly built
perl and the libraries under whatever "INST_TOP" points to in the
Makefile. It will also install the pod documentation under
"$INST_TOP\$INST_VER\lib\pod" and HTML versions of the same under
"$INST_TOP\$INST_VER\lib\pod\html".

To use the Perl you just installed you will need to add a new entry to
your PATH environment variable: "$INST_TOP\bin", e.g.

set PATH=c:\perl\bin;%PATH%

If you opted to uncomment "INST_VER" and "INST_ARCH" in the makefile
then the installation structure is a little more complicated and you
will need to add two new PATH components instead:
"$INST_TOP\$INST_VER\bin" and "$INST_TOP\$INST_VER\bin\$ARCHNAME", e.g.

set PATH=c:\perl\5.6.0\bin;c:\perl\5.6.0\bin\MSWin32-x86;%PATH%

Usage Hints for Perl on Windows
Environment Variables
The installation paths that you set during the build get compiled
into perl, so you don't have to do anything additional to start
using that perl (except add its location to your PATH variable).

If you put extensions in unusual places, you can set PERL5LIB to a
list of paths separated by semicolons where you want perl to look
for libraries. Look for descriptions of other environment variables
you can set in perlrun.

You can also control the shell that perl uses to run system() and
backtick commands via PERL5SHELL. See perlrun.

Perl does not depend on the registry, but it can look up certain
default values if you choose to put them there unless disabled at
build time with USE_NO_REGISTRY. On Perl process start Perl checks
if "HKEY_CURRENT_USER\Software\Perl" and
"HKEY_LOCAL_MACHINE\Software\Perl" exist. If the keys exists, they
will be checked for remainder of the Perl process's run life for
certain entries. Entries in "HKEY_CURRENT_USER\Software\Perl"
override entries in "HKEY_LOCAL_MACHINE\Software\Perl". One or more
of the following entries (of type REG_SZ or REG_EXPAND_SZ) may be
set in the keys:

lib-$] version-specific standard library path to add to @INC
lib standard library path to add to @INC
sitelib-$] version-specific site library path to add to @INC
sitelib site library path to add to @INC
vendorlib-$] version-specific vendor library path to add to @INC
vendorlib vendor library path to add to @INC
PERL* fallback for all %ENV lookups that begin with "PERL"

Note the $] in the above is not literal. Substitute whatever
version of perl you want to honor that entry, e.g. 5.6.0. Paths
must be separated with semicolons, as usual on Windows.

File Globbing
By default, perl handles file globbing using the File::Glob
extension, which provides portable globbing.

If you want perl to use globbing that emulates the quirks of DOS
filename conventions, you might want to consider using File::DosGlob
to override the internal glob() implementation. See File::DosGlob
for details.

Using perl from the command line
If you are accustomed to using perl from various command-line shells
found in UNIX environments, you will be less than pleased with what
Windows offers by way of a command shell.

The crucial thing to understand about the Windows environment is
that the command line you type in is processed twice before Perl
sees it. First, your command shell (usually CMD.EXE) preprocesses
the command line, to handle redirection, environment variable
expansion, and location of the executable to run. Then, the perl
executable splits the remaining command line into individual
arguments, using the C runtime library upon which Perl was built.

It is particularly important to note that neither the shell nor the
C runtime do any wildcard expansions of command-line arguments (so
wildcards need not be quoted). Also, the quoting behaviours of the
shell and the C runtime are rudimentary at best (and may, if you are
using a non-standard shell, be inconsistent). The only (useful)
quote character is the double quote ("). It can be used to protect
spaces and other special characters in arguments.

The Windows documentation describes the shell parsing rules here:
<https://docs.microsoft.com/en-us/windows-server/administration/windows-commands/cmd>
and the C runtime parsing rules here:
<https://msdn.microsoft.com/en-us/library/17w5ykft%28v=VS.100%29.aspx>.

Here are some further observations based on experiments: The C
runtime breaks arguments at spaces and passes them to programs in
argc/argv. Double quotes can be used to prevent arguments with
spaces in them from being split up. You can put a double quote in
an argument by escaping it with a backslash and enclosing the whole
argument within double quotes. The backslash and the pair of double
quotes surrounding the argument will be stripped by the C runtime.

The file redirection characters "<", ">", and "|" can be quoted by
double quotes (although there are suggestions that this may not
always be true). Single quotes are not treated as quotes by the
shell or the C runtime, they don't get stripped by the shell (just
to make this type of quoting completely useless). The caret "^" has
also been observed to behave as a quoting character, but this
appears to be a shell feature, and the caret is not stripped from
the command line, so Perl still sees it (and the C runtime phase
does not treat the caret as a quote character).

Here are some examples of usage of the "cmd" shell:

This prints two doublequotes:

perl -e "print '\"\"' "

This does the same:

perl -e "print \"\\\"\\\"\" "

This prints "bar" and writes "foo" to the file "blurch":

perl -e "print 'foo'; print STDERR 'bar'" > blurch

This prints "foo" ("bar" disappears into nowhereland):

perl -e "print 'foo'; print STDERR 'bar'" 2> nul

This prints "bar" and writes "foo" into the file "blurch":

perl -e "print 'foo'; print STDERR 'bar'" 1> blurch

This pipes "foo" to the "less" pager and prints "bar" on the
console:

perl -e "print 'foo'; print STDERR 'bar'" | less

This pipes "foo\nbar\n" to the less pager:

perl -le "print 'foo'; print STDERR 'bar'" 2>&1 | less

This pipes "foo" to the pager and writes "bar" in the file "blurch":

perl -e "print 'foo'; print STDERR 'bar'" 2> blurch | less

Discovering the usefulness of the "command.com" shell on Windows 9x
is left as an exercise to the reader :)

One particularly pernicious problem with the 4NT command shell for
Windows is that it (nearly) always treats a % character as
indicating that environment variable expansion is needed. Under
this shell, it is therefore important to always double any %
characters which you want Perl to see (for example, for hash
variables), even when they are quoted.

Building Extensions
The Comprehensive Perl Archive Network (CPAN) offers a wealth of
extensions, some of which require a C compiler to build. Look in
<https://www.cpan.org/> for more information on CPAN.

Note that not all of the extensions available from CPAN may work in
the Windows environment; you should check the information at
<https://www.cpantesters.org/> before investing too much effort into
porting modules that don't readily build.

Most extensions (whether they require a C compiler or not) can be
built, tested and installed with the standard mantra:

perl Makefile.PL
$MAKE
$MAKE test
$MAKE install

where $MAKE is whatever 'make' program you have configured perl to
use. Use "perl -V:make" to find out what this is. Some extensions
may not provide a testsuite (so "$MAKE test" may not do anything or
fail), but most serious ones do.

It is important that you use a supported 'make' program, and ensure
Config.pm knows about it.

Note that MakeMaker actually emits makefiles with different syntax
depending on what 'make' it thinks you are using. Therefore, it is
important that one of the following values appears in Config.pm:

make='nmake' # MakeMaker emits nmake syntax
any other value # MakeMaker emits generic make syntax
(e.g GNU make, or Perl make)

If the value doesn't match the 'make' program you want to use, edit
Config.pm to fix it.

If a module implements XSUBs, you will need one of the supported C
compilers. You must make sure you have set up the environment for
the compiler for command-line compilation before running "perl
Makefile.PL" or any invocation of make.

If a module does not build for some reason, look carefully for why
it failed, and report problems to the module author. If it looks
like the extension building support is at fault, report that with
full details of how the build failed using the GitHub issue tracker
at <https://github.com/Perl/perl5/issues>.

Command-line Wildcard Expansion
The default command shells on DOS descendant operating systems (such
as they are) usually do not expand wildcard arguments supplied to
programs. They consider it the application's job to handle that.
This is commonly achieved by linking the application (in our case,
perl) with startup code that the C runtime libraries usually
provide. However, doing that results in incompatible perl versions
(since the behavior of the argv expansion code differs depending on
the compiler, and it is even buggy on some compilers). Besides, it
may be a source of frustration if you use such a perl binary with an
alternate shell that *does* expand wildcards.

Instead, the following solution works rather well. The nice things
about it are 1) you can start using it right away; 2) it is more
powerful, because it will do the right thing with a pattern like
*/*/*.c; 3) you can decide whether you do/don't want to use it; and
4) you can extend the method to add any customizations (or even
entirely different kinds of wildcard expansion).

C:\> copy con c:\perl\lib\Wild.pm
# Wild.pm - emulate shell @ARGV expansion on shells that don't
use File::DosGlob;
@ARGV = map {
my @g = File::DosGlob::glob($_) if /[*?]/;
@g ? @g : $_;
} @ARGV;
1;
^Z
C:\> set PERL5OPT=-MWild
C:\> perl -le "for (@ARGV) { print }" */*/perl*.c
p4view/perl/perl.c
p4view/perl/perlio.c
p4view/perl/perly.c
perl5.005/win32/perlglob.c
perl5.005/win32/perllib.c
perl5.005/win32/perlglob.c
perl5.005/win32/perllib.c
perl5.005/win32/perlglob.c
perl5.005/win32/perllib.c

Note there are two distinct steps there: 1) You'll have to create
Wild.pm and put it in your perl lib directory. 2) You'll need to set
the PERL5OPT environment variable. If you want argv expansion to be
the default, just set PERL5OPT in your default startup environment.

If you are using the Visual C compiler, you can get the C runtime's
command line wildcard expansion built into perl binary. The
resulting binary will always expand unquoted command lines, which
may not be what you want if you use a shell that does that for you.
The expansion done is also somewhat less powerful than the approach
suggested above.

Notes on 64-bit Windows
Windows .NET Server supports the LLP64 data model on the Intel
Itanium architecture.

The LLP64 data model is different from the LP64 data model that is
the norm on 64-bit Unix platforms. In the former, "int" and "long"
are both 32-bit data types, while pointers are 64 bits wide. In
addition, there is a separate 64-bit wide integral type, "__int64".
In contrast, the LP64 data model that is pervasive on Unix platforms
provides "int" as the 32-bit type, while both the "long" type and
pointers are of 64-bit precision. Note that both models provide for
64-bits of addressability.

64-bit Windows running on Itanium is capable of running 32-bit x86
binaries transparently. This means that you could use a 32-bit
build of Perl on a 64-bit system. Given this, why would one want to
build a 64-bit build of Perl? Here are some reasons why you would
bother:

• A 64-bit native application will run much more efficiently on
Itanium hardware.

• There is no 2GB limit on process size.

• Perl automatically provides large file support when built under
64-bit Windows.

• Embedding Perl inside a 64-bit application.

Running Perl Scripts
Perl scripts on UNIX use the "#!" (a.k.a "shebang") line to indicate to
the OS that it should execute the file using perl. Windows has no
comparable means to indicate arbitrary files are executables.

Instead, all available methods to execute plain text files on Windows
rely on the file "extension". There are three methods to use this to
execute perl scripts:

1. There is a facility called "file extension associations". This
can be manipulated via the two commands "assoc" and "ftype" that
come standard with Windows. Type "ftype /?" for a complete
example of how to set this up for perl scripts (Say what? You
thought Windows wasn't perl-ready? :).

2. Since file associations don't work everywhere, and there are
reportedly bugs with file associations where it does work, the
old method of wrapping the perl script to make it look like a
regular batch file to the OS, may be used. The install process
makes available the "pl2bat.bat" script which can be used to
wrap perl scripts into batch files. For example:

pl2bat foo.pl

will create the file "FOO.BAT". Note "pl2bat" strips any .pl
suffix and adds a .bat suffix to the generated file.

If you use the 4DOS/NT or similar command shell, note that
"pl2bat" uses the "%*" variable in the generated batch file to
refer to all the command line arguments, so you may need to make
sure that construct works in batch files. As of this writing,
4DOS/NT users will need a "ParameterChar = *" statement in their
4NT.INI file or will need to execute "setdos /p*" in the 4DOS/NT
startup file to enable this to work.

3. Using "pl2bat" has a few problems: the file name gets changed,
so scripts that rely on $0 to find what they must do may not run
properly; running "pl2bat" replicates the contents of the
original script, and so this process can be maintenance
intensive if the originals get updated often. A different
approach that avoids both problems is possible.

A script called "runperl.bat" is available that can be copied to
any filename (along with the .bat suffix). For example, if you
call it "foo.bat", it will run the file "foo" when it is
executed. Since you can run batch files on Windows platforms
simply by typing the name (without the extension), this
effectively runs the file "foo", when you type either "foo" or
"foo.bat". With this method, "foo.bat" can even be in a
different location than the file "foo", as long as "foo" is
available somewhere on the PATH. If your scripts are on a
filesystem that allows symbolic links, you can even avoid
copying "runperl.bat".

Here's a diversion: copy "runperl.bat" to "runperl", and type
"runperl". Explain the observed behavior, or lack thereof. :)
Hint: .gnidnats llits er'uoy fi ,"lrepnur" eteled :tniH

Miscellaneous Things
A full set of HTML documentation is installed, so you should be able to
use it if you have a web browser installed on your system.

"perldoc" is also a useful tool for browsing information contained in
the documentation, especially in conjunction with a pager like "less"
(recent versions of which have Windows support). You may have to set
the PAGER environment variable to use a specific pager. "perldoc -f
foo" will print information about the perl operator "foo".

One common mistake when using this port with a GUI library like "Tk" is
assuming that Perl's normal behavior of opening a command-line window
will go away. This isn't the case. If you want to start a copy of
"perl" without opening a command-line window, use the "wperl" executable
built during the installation process. Usage is exactly the same as
normal "perl" on Windows, except that options like "-h" don't work
(since they need a command-line window to print to).

If you find bugs in perl, you can report them to
<https://github.com/Perl/perl5/issues>.

BUGS AND CAVEATS
Norton AntiVirus interferes with the build process, particularly if set
to "AutoProtect, All Files, when Opened". Unlike large applications the
perl build process opens and modifies a lot of files. Having the
AntiVirus scan each and every one slows build the process significantly.
Worse, with PERLIO=stdio the build process fails with peculiar messages
as the virus checker interacts badly with miniperl.exe writing configure
files (it seems to either catch file part written and treat it as
suspicious, or virus checker may have it "locked" in a way which
inhibits miniperl updating it). The build does complete with

set PERLIO=perlio

but that may be just luck. Other AntiVirus software may have similar
issues.

A git GUI shell extension for Windows such as TortoiseGit will cause the
build and later "make test" to run much slower since every file is
checked for its git status as soon as it is created and/or modified.
TortoiseGit doesn't cause any test failures or build problems unlike the
antivirus software described above, but it does cause similar slowness.
It is suggested to use Task Manager to look for background processes
which use high CPU amounts during the building process.

Some of the built-in functions do not act exactly as documented in
perlfunc, and a few are not implemented at all. To avoid surprises,
particularly if you have had prior exposure to Perl in other operating
environments or if you intend to write code that will be portable to
other environments, see perlport for a reasonably definitive list of
these differences.

Not all extensions available from CPAN may build or work properly in the
Windows environment. See "Building Extensions".

Most socket() related calls are supported, but they may not behave as on
Unix platforms. See perlport for the full list.

Signal handling may not behave as on Unix platforms (where it doesn't
exactly "behave", either :). For instance, calling die() or exit() from
signal handlers will cause an exception, since most implementations of
signal() on Windows are severely crippled. Thus, signals may work only
for simple things like setting a flag variable in the handler. Using
signals under this port should currently be considered unsupported.

Please report detailed descriptions of any problems and solutions that
you may find at <<https://github.com/Perl/perl5/issues>>, along with the
output produced by "perl -V".

ACKNOWLEDGEMENTS
The use of a camel with the topic of Perl is a trademark of O'Reilly and
Associates, Inc. Used with permission.

AUTHORS
Gary Ng <71564.1743@CompuServe.COM>
Gurusamy Sarathy <gsar@activestate.com>
Nick Ing-Simmons <nick@ing-simmons.net>
Jan Dubois <jand@activestate.com>
Steve Hay <steve.m.hay@googlemail.com>

This document is maintained by Jan Dubois.