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William J. Middleton


perlwin32 - Perl under Win32


These are instructions for building Perl under Windows NT (versions 3.51 or 4.0), using Visual C++ (versions 2.0 through 5.0) or Borland C++ (version 5.x). Currently, this port may also build under Windows95, but you can expect problems stemming from the unmentionable command shell that infests that platform. Note this caveat is only about building perl. Once built, you should be able to use it on either Win32 platform (modulo the problems arising from the inferior command shell).


Before you start, you should glance through the README file found in the top-level directory where 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 two other options for building a perl that will work on Windows NT: the README.cygwin32 and README.os2 files, which each give a different set of rules to build a Perl that will work on Win32 platforms. Those two methods 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 those files.

This set of instructions is meant to describe a so-called "native" port of Perl to Win32 platforms. The resulting Perl requires no additional software to run (other than what came with your operating system). Currently, this port is capable of using either the Microsoft Visual C++ compiler, or the Borland C++ compiler. The ultimate goal is to support the other major compilers that can generally be used to build Win32 applications.

This port currently 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" below for general hints about this.

Setting Up

Command Shell

Use the default "cmd" shell that comes with NT. In particular, do *not* use the 4DOS/NT shell. The Makefile has commands that are not compatible with that shell. The Makefile also has known incompatibilites with the default shell that comes with Windows95, so building under Windows95 should be considered "unsupported".

Borland C++

If you are using the Borland compiler, you will need dmake, a freely available make that has very nice macro features and parallelability. (The make that Borland supplies is seriously crippled, and will not work for MakeMaker builds--if you *have* to bug someone about this, I suggest you bug Borland to fix their make :)

A port of dmake for win32 platforms is available from "http://www-personal.umich.edu/~gsar/dmake-4.0-win32.tar.gz". Fetch and install dmake somewhere on your path. Also make sure you copy the Borland dmake.ini file to some location where you keep *.ini files. If you use the binary that comes with the above port, you will need to set INIT in your environment to the directory where you put the dmake.ini file.

Microsoft Visual C++

The NMAKE that comes with Visual C++ will suffice for building. If you did not choose to always initialize the Visual C++ compilation environment variables when you installed Visual C++ on your system, you will need to run the VCVARS32.BAT file usually found somewhere like C:\MSDEV4.2\BIN. This will set your build environment.

You can also use dmake to build using Visual C++, provided: you copied the dmake.ini for Visual C++; set INIT to point to the directory where you put it, as above; and edit win32/config.vc and change "make=nmake" to "make=dmake". The last step is only essential if you want to use dmake to be your default make for building extensions using MakeMaker.


Depending on how you extracted the distribution, you have to make sure some of the files are writable by you. The easiest way to make sure of this is to execute:

        attrib -R *.* /S

from the perl toplevel directory. You don't have to do this if you used the right tools to extract the files in the standard distribution, but it doesn't hurt to do so.


  • 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++ ver. 2.0 and above, and a dmake "makefile.mk" that will work for both Borland and Visual C++ builds. The defaults in the dmake makefile are setup to build using the Borland compiler.

  • Edit the Makefile (or makefile.mk, if using dmake) and change the values of INST_DRV and INST_TOP if you want perl to be installed in a location other than "C:\PERL". If you are using Visual C++ ver. 2.0, uncomment the line that sets "CCTYPE=MSVC20".

    You will also have to make sure CCHOME points to wherever you installed your compiler.

  • Type "nmake" (or "dmake" if you are using that make).

    This should build everything. Specifically, it will create perl.exe, perl.dll, and perlglob.exe 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.

    The build process may produce "harmless" compiler warnings (more or less copiously, depending on how picky your compiler gets). The maintainers are aware of these warnings, thankyouverymuch. :)

    When building using Visual C++, a perl95.exe will also get built. This executable is only needed on Windows95, and should be used instead of perl.exe, and then only if you want sockets to work properly on Windows95. This is necessitated by a bug in the Microsoft C Runtime that cannot be worked around in the "normal" perl.exe. Again, if this bugs you, please bug Microsoft :). perl95.exe gets built with its own private copy of the C Runtime that is not accessible to extensions (which see the DLL version of the CRT). Be aware, therefore, that this perl95.exe will have esoteric problems with extensions like perl/Tk that themselves use the C Runtime heavily, or want to free() pointers malloc()-ed by perl.

    You can avoid the perl95.exe problems completely if you use Borland C++ for building perl (perl95.exe is not needed and will not be built in that case).


Type "nmake test" (or "dmake test"). This will run most of the tests from the testsuite (many tests will be skipped, and but no test should fail).

If some tests do fail, it may be because you are using a different command shell than the native "cmd.exe".

If you used the Borland compiler, you may see a failure in op/taint.t arising from the inability to find the Borland Runtime DLLs on the system default path. You will need to copy the DLLs reported by the messages from where Borland chose to install it, into the Windows system directory (usually somewhere like C:\WINNT\SYSTEM32), and rerun the test.

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


Type "nmake install" (or "dmake install"). This will put the newly built perl and the libraries under "C:\perl" (actually whatever you set INST_TOP to in the Makefile). It will also install the pod documentation under $INST_TOP\lib\pod and HTML versions of the same under $INST_TOP\lib\pod\html. To use the Perl you just installed, set your PATH environment variable to "C:\perl\bin" (or $INST_TOP\bin, if you changed the default as above).

Usage Hints

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 the perlrun podpage.

Sometime in the future, some of the configuration information for perl will be moved into the Windows registry.

File Globbing

By default, perl spawns an external program to do file globbing. The install process installs both a perlglob.exe and a perlglob.bat that perl can use for this purpose. Note that with the default installation, perlglob.exe will be found by the system before perlglob.bat.

perlglob.exe relies on the argv expansion done by the C Runtime of the particular compiler you used, and therefore behaves very differently depending on the Runtime used to build it. To preserve compatiblity, perlglob.bat (a perl script/module that can be used portably) is installed. Besides being portable, perlglob.bat also offers enhanced globbing functionality.

If you want perl to use perlglob.bat instead of perlglob.exe, just delete perlglob.exe from the install location (or move it somewhere perl cannot find). Using File::DosGlob.pm (which is the same as perlglob.bat) to override the internal CORE::glob() works about 10 times faster than spawing perlglob.exe, and you should take this approach when writing new modules. 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 NT offers by way of a command shell.

The crucial thing to understand about the "cmd" shell (which is the default on Windows NT) is that it does not do any wildcard expansions of command-line arguments (so wildcards need not be quoted). It also provides only rudimentary quoting. The only (useful) quote character is the double quote ("). It can be used to protect spaces in arguments and other special characters. The Windows NT documentation has almost no description of how the quoting rules are implemented, but here are some general observations based on experiments: The shell breaks arguments at spaces and passes them to programs in argc/argv. Doublequotes 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 shell.

The file redirection characters "<", ">", and "|" cannot be quoted by double quotes (there are probably more such). Single quotes will protect those three file redirection characters, but the single quotes 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 (and doesn't get stripped by the shell also).

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 Windows95 is left as an exercise to the reader :)

Building Extensions

The Comprehensive Perl Archive Network (CPAN) offers a wealth of extensions, some of which require a C compiler to build. Look in http://www.perl.com/ for more information on CPAN.

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

    perl Makefile.PL
    $MAKE test
    $MAKE install

where $MAKE stands for NMAKE or DMAKE. Some extensions may not provide a testsuite (so "$MAKE test" may not do anything, or fail), but most serious ones do.

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.

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 perlbug utility.

Win32 Specific Extensions

A number of extensions specific to the Win32 platform are available from CPAN. You may find that many of these extensions are meant to be used under the Activeware port of Perl, which used to be the only native port for the Win32 platform. Since the Activeware port does not have adequate support for Perl's extension building tools, these extensions typically do not support those tools either, and therefore cannot be built using the generic steps shown in the previous section.

To ensure smooth transitioning of existing code that uses the Activeware port, there is a bundle of Win32 extensions that contains all of the Activeware extensions and most other Win32 extensions from CPAN in source form, along with many added bugfixes, and with MakeMaker support. This bundle is available at:


See the README in that distribution for building and installation instructions. Look for later versions that may be available at the same location.

It is expected that authors of Win32 specific extensions will begin distributing their work in MakeMaker compatible form subsequent to the 5.004 release of perl, at which point the need for a dedicated bundle such as the above should diminish.

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. Win32 has no comparable means to indicate arbitrary files are executables.

Instead, all available methods to execute plain text files on Win32 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" that will work in Windows NT 4.0. This can be manipulated via the two commands "assoc" and "ftype" that come standard with Windows NT 4.0. Type "ftype /?" for a complete example of how to set this up for perl scripts (Say what? You thought Windows NT 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 Win32 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 Win32 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".

If you find bugs in perl, you can run perlbug to create a bug report (you may have to send it manually if perlbug cannot find a mailer on your system).


This port should be considered beta quality software at the present time because some details are still in flux and there may be changes in any of these areas: build process, installation structure, supported utilities/modules, and supported perl functionality. In particular, functionality specific to the Win32 environment may ultimately be supported as either core modules or extensions. The beta status implies, among other things, that you should be prepared to recompile extensions when binary incompatibilites arise due to changes in the internal structure of the code.

An effort has been made to ensure that the DLLs produced by the two supported compilers are compatible with each other (despite the best efforts of the compiler vendors). Extension binaries produced by one compiler should also coexist with a perl binary built by a different compiler. In order to accomplish this, PERL.DLL provides a layer of runtime code that uses the C Runtime that perl was compiled with. Extensions which include "perl.h" will transparently access the functions in this layer, thereby ensuring that both perl and extensions use the same runtime functions.

If you have had prior exposure to Perl on Unix platforms, you will notice this port exhibits behavior different from what is documented. Most of the differences fall under one of these categories. We do not consider any of them to be serious limitations (especially when compared to the limited nature of some of the Win32 OSes themselves :)

  • stat() and lstat() functions may not behave as documented. They may return values that bear no resemblance to those reported on Unix platforms, and some fields (like the the one for inode) may be completely bogus.

  • The following functions are currently unavailable: fork(), dump(), chown(), link(), symlink(), chroot(), setpgrp(), getpgrp(), setpriority(), getpriority(), syscall(), fcntl(). This list is possibly very incomplete.

  • crypt() is not available due to silly export restrictions. It may become available when the laws change. Meanwhile, look in CPAN for extensions that provide it.

  • Various socket() related calls are supported, but they may not behave as on Unix platforms.

  • The four-argument select() call is only supported on sockets.

  • $? ends up with the exitstatus of the subprocess (this is different from Unix, where the exitstatus is actually given by "$? >> 8"). Failure to spawn() the subprocess is indicated by setting $? to "255<<8". This is subject to change.

  • Building modules available on CPAN is mostly supported, but this hasn't been tested much yet. Expect strange problems, and be prepared to deal with the consequences.

  • utime(), times() and process-related functions may not behave as described in the documentation, and some of the returned values or effects may be bogus.

  • 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 Win32 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.

  • File globbing may not behave as on Unix platforms. In particular, if you don't use perlglob.bat for globbing, it will understand wildcards only in the filename component (and not in the pathname). In other words, something like "print <*/*.pl>" will not print all the perl scripts in all the subdirectories one level under the current one (like it does on UNIX platforms). perlglob.exe is also dependent on the particular implementation of wildcard expansion in the vendor libraries used to build it (which varies wildly at the present time). Using perlglob.bat (or File::DosGlob) avoids these limitations, but still only provides DOS semantics (read "warts") for globbing.

Please send detailed descriptions of any problems and solutions that you may find to <perlbug@perl.com>, along with the output produced by perl -V.


    Gary Ng <71564.1743@CompuServe.COM>

    Gurusamy Sarathy <gsar@umich.edu>

    Nick Ing-Simmons <nick@ni-s.u-net.com>

This document is maintained by Gurusamy Sarathy.




This port was originally contributed by Gary Ng around 5.003_24, and borrowed from the Hip Communications port that was available at the time.

Nick Ing-Simmons and Gurusamy Sarathy have made numerous and sundry hacks since then.

Borland support was added in 5.004_01 (Gurusamy Sarathy).

Last updated: 25 July 1997