perlwin32.pod

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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 :)

=item 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
    $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.

=item 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: 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 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.

=item 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
ActiveState port, there is a bundle of Win32 extensions that contains
all of the ActiveState 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:

   http://www.perl.com/CPAN/authors/id/GSAR/libwin32-0.12.zip

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

=item 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:

=over 8

=item 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? :).

=item 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.

=item 3

Using "pl2bat" has a few problems:  the file name gets changed,
so scripts that rely on C<$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

=back

=item 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.

C<perldoc> is also a useful tool for browsing information contained
in the documentation, especially in conjunction with a pager
like C<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 C<perlbug> to create a
bug report (you may have to send it manually if C<perlbug> cannot
find a mailer on your system).

=back

=head1 BUGS AND CAVEATS

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 :)

=over 8

=item *

C<stat()> and C<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.

=item *

The following functions are currently unavailable: C<fork()>,
C<dump()>, C<chown()>, C<link()>, C<symlink()>, C<chroot()>,
C<setpgrp()> and related security functions, C<setpriority()>,
C<getpriority()>, C<syscall()>, C<fcntl()>, C<getpw*()>,
C<msg*()>, C<shm*()>, C<sem*()>, C<alarm()>, C<socketpair()>,
C<*netent()>, C<*protoent()>, C<*servent()>, C<*hostent()>,
C<getnetby*()>.
This list is possibly incomplete.

=item *

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

=item *

The four-argument C<select()> call is only supported on sockets.

=item *

The C<ioctl()> call is only supported on sockets (where it provides the
functionality of ioctlsocket() in the Winsock API).

=item *

Failure to spawn() a subprocess is indicated by setting $? to "255 << 8".
C<$?> is set in a way compatible with Unix (i.e. the exitstatus of the
subprocess is obtained by "$? >> 8", as described in the documentation).

=item *

You can expect problems building modules available on CPAN if you
build perl itself with -DUSE_THREADS.  These problems should be resolved
as we get closer to 5.005.

=item *

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

=item *

Signal handling may not behave as on Unix platforms (where it
doesn't exactly "behave", either :).  For instance, calling C<die()>
or C<exit()> from signal handlers will cause an exception, since most
implementations of C<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.

=item *

C<kill()> is implemented, but doesn't have the semantics of
C<raise()>, i.e. it doesn't send a signal to the identified process
like it does on Unix platforms.  Instead it immediately calls
C<TerminateProcess(process,signal)>.  Thus the signal argument is
used to set the exit-status of the terminated process.  This behavior
may change in future.

=item *

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.

=back

Please send detailed descriptions of any problems and solutions that 
you may find to <F<[e-mail]>>, along with the output produced
by C<perl -V>.

=head1 AUTHORS

=over 4

Gary Ng E<lt>[e-mail]<gt>

Gurusamy Sarathy E<lt>[e-mail]<gt>

Nick Ing-Simmons E<lt>[e-mail]<gt>

=back

This document is maintained by Gurusamy Sarathy.

=head1 SEE ALSO

L<perl>

=head1 HISTORY

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: 12 July 1998

=cut