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database/perl/lib/pods/perlcygwin.pod

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+If you read this file _as_is_, just ignore the funny characters you
+see. It is written in the POD format (see F<pod/perlpod.pod>) which is
+specially designed to be readable as is.
+
+=head1 NAME
+
+perlcygwin - Perl for Cygwin
+
+=head1 SYNOPSIS
+
+This document will help you configure, make, test and install Perl
+on Cygwin.  This document also describes features of Cygwin that will
+affect how Perl behaves at runtime.
+
+B<NOTE:> There are pre-built Perl packages available for Cygwin and a
+version of Perl is provided in the normal Cygwin install.  If you do
+not need to customize the configuration, consider using one of those
+packages.
+
+
+=head1 PREREQUISITES FOR COMPILING PERL ON CYGWIN
+
+=head2 Cygwin = GNU+Cygnus+Windows (Don't leave UNIX without it)
+
+The Cygwin tools are ports of the popular GNU development tools for Win32
+platforms.  They run thanks to the Cygwin library which provides the UNIX
+system calls and environment these programs expect.  More information
+about this project can be found at:
+
+L<https://www.cygwin.com/>
+
+A recent net or commercial release of Cygwin is required.
+
+At the time this document was last updated, Cygwin 1.7.16 was current.
+
+
+=head2 Cygwin Configuration
+
+While building Perl some changes may be necessary to your Cygwin setup so
+that Perl builds cleanly.  These changes are B<not> required for normal
+Perl usage.
+
+B<NOTE:> The binaries that are built will run on all Win32 versions.
+They do not depend on your host system (WinXP/Win2K/Win7) or your
+Cygwin configuration (binary/text mounts, cvgserver).
+The only dependencies come from hard-coded pathnames like F</usr/local>.
+However, your host system and Cygwin configuration will affect Perl's
+runtime behavior (see L</"TEST">).
+
+=over 4
+
+=item * C<PATH>
+
+Set the C<PATH> environment variable so that Configure finds the Cygwin
+versions of programs. Any not-needed Windows directories should be removed or
+moved to the end of your C<PATH>.
+
+=item * I<nroff>
+
+If you do not have I<nroff> (which is part of the I<groff> package),
+Configure will B<not> prompt you to install I<man> pages.
+
+=back
+
+=head1 CONFIGURE PERL ON CYGWIN
+
+The default options gathered by Configure with the assistance of
+F<hints/cygwin.sh> will build a Perl that supports dynamic loading
+(which requires a shared F<cygperl5_16.dll>).
+
+This will run Configure and keep a record:
+
+  ./Configure 2>&1 | tee log.configure
+
+If you are willing to accept all the defaults run Configure with B<-de>.
+However, several useful customizations are available.
+
+=head2 Stripping Perl Binaries on Cygwin
+
+It is possible to strip the EXEs and DLLs created by the build process.
+The resulting binaries will be significantly smaller.  If you want the
+binaries to be stripped, you can either add a B<-s> option when Configure
+prompts you,
+
+  Any additional ld flags (NOT including libraries)? [none] -s
+  Any special flags to pass to g++ to create a dynamically loaded
+  library?
+  [none] -s
+  Any special flags to pass to gcc to use dynamic linking? [none] -s
+
+or you can edit F<hints/cygwin.sh> and uncomment the relevant variables
+near the end of the file.
+
+=head2 Optional Libraries for Perl on Cygwin
+
+Several Perl functions and modules depend on the existence of
+some optional libraries.  Configure will find them if they are
+installed in one of the directories listed as being used for library
+searches.  Pre-built packages for most of these are available from
+the Cygwin installer.
+
+=over 4
+
+=item * C<-lcrypt>
+
+The crypt package distributed with Cygwin is a Linux compatible 56-bit
+DES crypt port by Corinna Vinschen.
+
+Alternatively, the crypt libraries in GNU libc have been ported to Cygwin.
+
+As of libcrypt 1.3 (March 2016), you will need to install the
+libcrypt-devel package for Configure to detect crypt().
+
+=item * C<-lgdbm_compat> (C<use GDBM_File>)
+
+GDBM is available for Cygwin.
+
+NOTE: The GDBM library only works on NTFS partitions.
+
+=item * C<-ldb> (C<use DB_File>)
+
+BerkeleyDB is available for Cygwin.
+
+NOTE: The BerkeleyDB library only completely works on NTFS partitions.
+
+=item * C<cygserver> (C<use IPC::SysV>)
+
+A port of SysV IPC is available for Cygwin.
+
+NOTE: This has B<not> been extensively tested.  In particular,
+C<d_semctl_semun> is undefined because it fails a Configure test
+and on Win9x the I<shm*()> functions seem to hang.  It also creates
+a compile time dependency because F<perl.h> includes F<<sys/ipc.h>>
+and F<<sys/sem.h>> (which will be required in the future when compiling
+CPAN modules). CURRENTLY NOT SUPPORTED!
+
+=item * C<-lutil>
+
+Included with the standard Cygwin netrelease is the inetutils package
+which includes libutil.a.
+
+=back
+
+=head2 Configure-time Options for Perl on Cygwin
+
+The F<INSTALL> document describes several Configure-time options.  Some of
+these will work with Cygwin, others are not yet possible.  Also, some of
+these are experimental.  You can either select an option when Configure
+prompts you or you can define (undefine) symbols on the command line.
+
+=over 4
+
+=item * C<-Uusedl>
+
+Undefining this symbol forces Perl to be compiled statically.
+
+=item * C<-Dusemymalloc>
+
+By default Perl does not use the C<malloc()> included with the Perl source,
+because it was slower and not entirely thread-safe.  If you want to force
+Perl to build with the old -Dusemymalloc define this.
+
+=item * C<-Uuseperlio>
+
+Undefining this symbol disables the PerlIO abstraction.  PerlIO is now the
+default; it is not recommended to disable PerlIO.
+
+=item * C<-Dusemultiplicity>
+
+Multiplicity is required when embedding Perl in a C program and using
+more than one interpreter instance.  This is only required when you build
+a not-threaded perl with C<-Uuseithreads>.
+
+=item * C<-Uuse64bitint>
+
+By default Perl uses 64 bit integers.  If you want to use smaller 32 bit
+integers, define this symbol.
+
+=item * C<-Duselongdouble>
+
+I<gcc> supports long doubles (12 bytes).  However, several additional
+long double math functions are necessary to use them within Perl
+(I<{atan2, cos, exp, floor, fmod, frexp, isnan, log, modf, pow, sin, sqrt}l,
+strtold>).
+These are B<not> yet available with newlib, the Cygwin libc.
+
+=item * C<-Uuseithreads>
+
+Define this symbol if you want not-threaded faster perl.
+
+=item * C<-Duselargefiles>
+
+Cygwin uses 64-bit integers for internal size and position calculations,
+this will be correctly detected and defined by Configure.
+
+=item * C<-Dmksymlinks>
+
+Use this to build perl outside of the source tree.  Details can be
+found in the F<INSTALL> document.  This is the recommended way to
+build perl from sources.
+
+=back
+
+=head2 Suspicious Warnings on Cygwin
+
+You may see some messages during Configure that seem suspicious.
+
+=over 4
+
+=item * Win9x and C<d_eofnblk>
+
+Win9x does not correctly report C<EOF> with a non-blocking read on a
+closed pipe.  You will see the following messages:
+
+ But it also returns -1 to signal EOF, so be careful!
+ WARNING: you can't distinguish between EOF and no data!
+
+ *** WHOA THERE!!! ***
+     The recommended value for $d_eofnblk on this machine was
+     "define"!
+     Keep the recommended value? [y]
+
+At least for consistency with WinNT, you should keep the recommended
+value.
+
+=item * Compiler/Preprocessor defines
+
+The following error occurs because of the Cygwin C<#define> of
+C<_LONG_DOUBLE>:
+
+  Guessing which symbols your C compiler and preprocessor define...
+  try.c:<line#>: missing binary operator
+
+This failure does not seem to cause any problems.  With older gcc
+versions, "parse error" is reported instead of "missing binary
+operator".
+
+=back
+
+=head1 MAKE ON CYGWIN
+
+Simply run I<make> and wait:
+
+  make 2>&1 | tee log.make
+
+=head1 TEST ON CYGWIN
+
+There are two steps to running the test suite:
+
+  make test 2>&1 | tee log.make-test
+
+  cd t; ./perl harness 2>&1 | tee ../log.harness
+
+The same tests are run both times, but more information is provided when
+running as C<./perl harness>.
+
+Test results vary depending on your host system and your Cygwin
+configuration.  If a test can pass in some Cygwin setup, it is always
+attempted and explainable test failures are documented.  It is possible
+for Perl to pass all the tests, but it is more likely that some tests
+will fail for one of the reasons listed below.
+
+=head2 File Permissions on Cygwin
+
+UNIX file permissions are based on sets of mode bits for
+{read,write,execute} for each {user,group,other}.  By default Cygwin
+only tracks the Win32 read-only attribute represented as the UNIX file
+user write bit (files are always readable, files are executable if they
+have a F<.{com,bat,exe}> extension or begin with C<#!>, directories are
+always readable and executable).  On WinNT with the I<ntea> C<CYGWIN>
+setting, the additional mode bits are stored as extended file attributes.
+On WinNT with the default I<ntsec> C<CYGWIN> setting, permissions use the
+standard WinNT security descriptors and access control lists. Without one of
+these options, these tests will fail (listing not updated yet):
+
+  Failed Test           List of failed
+  ------------------------------------
+  io/fs.t               5, 7, 9-10
+  lib/anydbm.t          2
+  lib/db-btree.t        20
+  lib/db-hash.t         16
+  lib/db-recno.t        18
+  lib/gdbm.t            2
+  lib/ndbm.t            2
+  lib/odbm.t            2
+  lib/sdbm.t            2
+  op/stat.t             9, 20 (.tmp not an executable extension)
+
+=head2 NDBM_File and ODBM_File do not work on FAT filesystems
+
+Do not use NDBM_File or ODBM_File on FAT filesystem.  They can be
+built on a FAT filesystem, but many tests will fail:
+
+ ../ext/NDBM_File/ndbm.t       13  3328    71   59  83.10%  1-2 4 16-71
+ ../ext/ODBM_File/odbm.t      255 65280    ??   ??       %  ??
+ ../lib/AnyDBM_File.t           2   512    12    2  16.67%  1 4
+ ../lib/Memoize/t/errors.t      0   139    11    5  45.45%  7-11
+ ../lib/Memoize/t/tie_ndbm.t   13  3328     4    4 100.00%  1-4
+ run/fresh_perl.t                          97    1   1.03%  91
+
+If you intend to run only on FAT (or if using AnyDBM_File on FAT),
+run Configure with the -Ui_ndbm and -Ui_dbm options to prevent
+NDBM_File and ODBM_File being built.
+
+With NTFS (and no CYGWIN=nontsec), there should be no problems even if
+perl was built on FAT.
+
+=head2 C<fork()> failures in io_* tests
+
+A C<fork()> failure may result in the following tests failing:
+
+  ext/IO/lib/IO/t/io_multihomed.t
+  ext/IO/lib/IO/t/io_sock.t
+  ext/IO/lib/IO/t/io_unix.t
+
+See comment on fork in L</Miscellaneous> below.
+
+=head1 Specific features of the Cygwin port
+
+=head2 Script Portability on Cygwin
+
+Cygwin does an outstanding job of providing UNIX-like semantics on top of
+Win32 systems.  However, in addition to the items noted above, there are
+some differences that you should know about.  This is a very brief guide
+to portability, more information can be found in the Cygwin documentation.
+
+=over 4
+
+=item * Pathnames
+
+Cygwin pathnames are separated by forward (F</>) slashes, Universal
+Naming Codes (F<//UNC>) are also supported Since cygwin-1.7 non-POSIX
+pathnames are discouraged.  Names may contain all printable
+characters.
+
+File names are case insensitive, but case preserving.  A pathname that
+contains a backslash or drive letter is a Win32 pathname, and not
+subject to the translations applied to POSIX style pathnames, but
+cygwin will warn you, so better convert them to POSIX.
+
+For conversion we have C<Cygwin::win_to_posix_path()> and
+C<Cygwin::posix_to_win_path()>.
+
+Since cygwin-1.7 pathnames are UTF-8 encoded.
+
+=item * Text/Binary
+
+Since cygwin-1.7 textmounts are deprecated and strongly discouraged.
+
+When a file is opened it is in either text or binary mode.  In text mode
+a file is subject to CR/LF/Ctrl-Z translations.  With Cygwin, the default
+mode for an C<open()> is determined by the mode of the mount that underlies
+the file. See L</Cygwin::is_binmount>(). Perl provides a C<binmode()> function
+to set binary mode on files that otherwise would be treated as text.
+C<sysopen()> with the C<O_TEXT> flag sets text mode on files that otherwise
+would be treated as binary:
+
+    sysopen(FOO, "bar", O_WRONLY|O_CREAT|O_TEXT)
+
+C<lseek()>, C<tell()> and C<sysseek()> only work with files opened in binary
+mode.
+
+The text/binary issue is covered at length in the Cygwin documentation.
+
+=item * PerlIO
+
+PerlIO overrides the default Cygwin Text/Binary behaviour.  A file will
+always be treated as binary, regardless of the mode of the mount it lives
+on, just like it is in UNIX.  So CR/LF translation needs to be requested in
+either the C<open()> call like this:
+
+  open(FH, ">:crlf", "out.txt");
+
+which will do conversion from LF to CR/LF on the output, or in the
+environment settings (add this to your .bashrc):
+
+  export PERLIO=crlf
+
+which will pull in the crlf PerlIO layer which does LF -> CRLF conversion
+on every output generated by perl.
+
+=item * F<.exe>
+
+The Cygwin C<stat()>, C<lstat()> and C<readlink()> functions make the F<.exe>
+extension transparent by looking for F<foo.exe> when you ask for F<foo>
+(unless a F<foo> also exists).  Cygwin does not require a F<.exe>
+extension, but I<gcc> adds it automatically when building a program.
+However, when accessing an executable as a normal file (e.g., I<cp>
+in a makefile) the F<.exe> is not transparent.  The I<install> program
+included with Cygwin automatically appends a F<.exe> when necessary.
+
+=item * Cygwin vs. Windows process ids
+
+Cygwin processes have their own pid, which is different from the
+underlying windows pid.  Most posix compliant Proc functions expect
+the cygwin pid, but several Win32::Process functions expect the
+winpid. E.g. C<$$> is the cygwin pid of F</usr/bin/perl>, which is not
+the winpid.  Use C<Cygwin::pid_to_winpid()> and C<Cygwin::winpid_to_pid()>
+to translate between them.
+
+=item * Cygwin vs. Windows errors
+
+Under Cygwin, $^E is the same as $!.  When using L<Win32 API Functions|Win32>,
+use C<Win32::GetLastError()> to get the last Windows error.
+
+=item * rebase errors on fork or system
+
+Using C<fork()> or C<system()> out to another perl after loading multiple dlls
+may result on a DLL baseaddress conflict. The internal cygwin error
+looks like like the following:
+
+ 0 [main] perl 8916 child_info_fork::abort: data segment start:
+ parent (0xC1A000) != child(0xA6A000)
+
+or:
+
+ 183 [main] perl 3588 C:\cygwin\bin\perl.exe: *** fatal error -
+ unable to remap C:\cygwin\bin\cygsvn_subr-1-0.dll to same address
+ as parent(0x6FB30000) != 0x6FE60000 46 [main] perl 3488 fork: child
+ 3588 - died waiting for dll loading, errno11
+
+See L<https://cygwin.com/faq/faq-nochunks.html#faq.using.fixing-fork-failures>
+It helps if not too many DLLs are loaded in memory so the available address space is larger,
+e.g. stopping the MS Internet Explorer might help.
+
+Use the perlrebase or rebase utilities to resolve the conflicting dll addresses.
+The rebase package is included in the Cygwin setup. Use F<setup.exe>
+from L<https://cygwin.com/install.html> to install it.
+
+1. kill all perl processes and run C<perlrebase> or
+
+2. kill all cygwin processes and services, start dash from cmd.exe and run C<rebaseall>.
+
+=item * C<chown()>
+
+On WinNT C<chown()> can change a file's user and group IDs.  On Win9x C<chown()>
+is a no-op, although this is appropriate since there is no security model.
+
+=item * Miscellaneous
+
+File locking using the C<F_GETLK> command to C<fcntl()> is a stub that
+returns C<ENOSYS>.
+
+Win9x can not C<rename()> an open file (although WinNT can).
+
+The Cygwin C<chroot()> implementation has holes (it can not restrict file
+access by native Win32 programs).
+
+Inplace editing C<perl -i> of files doesn't work without doing a backup
+of the file being edited C<perl -i.bak> because of windowish restrictions,
+therefore Perl adds the suffix C<.bak> automatically if you use C<perl -i>
+without specifying a backup extension.
+
+=back
+
+=head2 Prebuilt methods:
+
+=over 4
+
+=item C<Cwd::cwd>
+
+Returns the current working directory.
+
+=item C<Cygwin::pid_to_winpid>
+
+Translates a cygwin pid to the corresponding Windows pid (which may or
+may not be the same).
+
+=item C<Cygwin::winpid_to_pid>
+
+Translates a Windows pid to the corresponding cygwin pid (if any).
+
+=item C<Cygwin::win_to_posix_path>
+
+Translates a Windows path to the corresponding cygwin path respecting
+the current mount points. With a second non-null argument returns an
+absolute path. Double-byte characters will not be translated.
+
+=item C<Cygwin::posix_to_win_path>
+
+Translates a cygwin path to the corresponding cygwin path respecting
+the current mount points. With a second non-null argument returns an
+absolute path. Double-byte characters will not be translated.
+
+=item C<Cygwin::mount_table()>
+
+Returns an array of [mnt_dir, mnt_fsname, mnt_type, mnt_opts].
+
+  perl -e 'for $i (Cygwin::mount_table) {print join(" ",@$i),"\n";}'
+  /bin c:\cygwin\bin system binmode,cygexec
+  /usr/bin c:\cygwin\bin system binmode
+  /usr/lib c:\cygwin\lib system binmode
+  / c:\cygwin system binmode
+  /cygdrive/c c: system binmode,noumount
+  /cygdrive/d d: system binmode,noumount
+  /cygdrive/e e: system binmode,noumount
+
+=item C<Cygwin::mount_flags>
+
+Returns the mount type and flags for a specified mount point.
+A comma-separated string of mntent->mnt_type (always
+"system" or "user"), then the mntent->mnt_opts, where
+the first is always "binmode" or "textmode".
+
+  system|user,binmode|textmode,exec,cygexec,cygdrive,mixed,
+  notexec,managed,nosuid,devfs,proc,noumount
+
+If the argument is "/cygdrive", then just the volume mount settings,
+and the cygdrive mount prefix are returned.
+
+User mounts override system mounts.
+
+  $ perl -e 'print Cygwin::mount_flags "/usr/bin"'
+  system,binmode,cygexec
+  $ perl -e 'print Cygwin::mount_flags "/cygdrive"'
+  binmode,cygdrive,/cygdrive
+
+=item C<Cygwin::is_binmount>
+
+Returns true if the given cygwin path is binary mounted, false if the
+path is mounted in textmode.
+
+=item C<Cygwin::sync_winenv>
+
+Cygwin does not initialize all original Win32 environment variables.
+See the bottom of this page L<https://cygwin.com/cygwin-ug-net/setup-env.html>
+for "Restricted Win32 environment".
+
+Certain Win32 programs called from cygwin programs might need some environment
+variable, such as e.g. ADODB needs %COMMONPROGRAMFILES%.
+Call Cygwin::sync_winenv() to copy all Win32 environment variables to your
+process and note that cygwin will warn on every encounter of non-POSIX paths.
+
+=back
+
+=head1 INSTALL PERL ON CYGWIN
+
+This will install Perl, including I<man> pages.
+
+  make install 2>&1 | tee log.make-install
+
+NOTE: If C<STDERR> is redirected C<make install> will B<not> prompt
+you to install I<perl> into F</usr/bin>.
+
+You may need to be I<Administrator> to run C<make install>.  If you
+are not, you must have write access to the directories in question.
+
+Information on installing the Perl documentation in HTML format can be
+found in the F<INSTALL> document.
+
+=head1 MANIFEST ON CYGWIN
+
+These are the files in the Perl release that contain references to Cygwin.
+These very brief notes attempt to explain the reason for all conditional
+code.  Hopefully, keeping this up to date will allow the Cygwin port to
+be kept as clean as possible.
+
+=over 4
+
+=item Documentation
+
+ INSTALL README.cygwin README.win32 MANIFEST
+ pod/perl.pod pod/perlport.pod pod/perlfaq3.pod
+ pod/perldelta.pod pod/perl5004delta.pod pod/perl56delta.pod
+ pod/perl561delta.pod pod/perl570delta.pod pod/perl572delta.pod
+ pod/perl573delta.pod pod/perl58delta.pod pod/perl581delta.pod
+ pod/perl590delta.pod pod/perlhist.pod pod/perlmodlib.pod
+ pod/perltoc.pod Porting/Glossary pod/perlgit.pod
+ Porting/checkAUTHORS.pl
+ dist/Cwd/Changes ext/Compress-Raw-Zlib/Changes
+ dist/Time-HiRes/Changes
+ ext/Compress-Raw-Zlib/README ext/Compress-Zlib/Changes
+ ext/DB_File/Changes ext/Encode/Changes ext/Sys-Syslog/Changes
+ ext/Win32API-File/Changes
+ lib/ExtUtils/CBuilder/Changes lib/ExtUtils/Changes
+ lib/ExtUtils/NOTES lib/ExtUtils/PATCHING lib/ExtUtils/README
+ lib/Net/Ping/Changes lib/Test/Harness/Changes
+ lib/Term/ANSIColor/ChangeLog lib/Term/ANSIColor/README
+ README.symbian symbian/TODO
+
+=item Build, Configure, Make, Install
+
+ cygwin/Makefile.SHs
+ ext/IPC/SysV/hints/cygwin.pl
+ ext/NDBM_File/hints/cygwin.pl
+ ext/ODBM_File/hints/cygwin.pl
+ hints/cygwin.sh
+ Configure             - help finding hints from uname,
+                         shared libperl required for dynamic loading
+ Makefile.SH Cross/Makefile-cross-SH
+                       - linklibperl
+ Porting/patchls       - cygwin in port list
+ installman            - man pages with :: translated to .
+ installperl           - install dll, install to 'pods'
+ makedepend.SH         - uwinfix
+ regen_lib.pl          - file permissions
+
+ NetWare/Makefile
+ plan9/mkfile
+ symbian/sanity.pl symbian/sisify.pl
+ hints/uwin.sh
+ vms/descrip_mms.template
+ win32/Makefile win32/makefile.mk
+
+=item Tests
+
+ t/io/fs.t             - no file mode checks if not ntsec
+                         skip rename() check when not
+                         check_case:relaxed
+ t/io/tell.t           - binmode
+ t/lib/cygwin.t        - builtin cygwin function tests
+ t/op/groups.t         - basegroup has ID = 0
+ t/op/magic.t          - $^X/symlink WORKAROUND, s/.exe//
+ t/op/stat.t           - no /dev, skip Win32 ftCreationTime quirk
+                         (cache manager sometimes preserves ctime of
+                         file previously created and deleted), no -u
+                         (setuid)
+ t/op/taint.t          - can't use empty path under Cygwin Perl
+ t/op/time.t           - no tzset()
+
+=item Compiled Perl Source
+
+ EXTERN.h              - __declspec(dllimport)
+ XSUB.h                - __declspec(dllexport)
+ cygwin/cygwin.c       - os_extras (getcwd, spawn, and several
+                         Cygwin:: functions)
+ perl.c                - os_extras, -i.bak
+ perl.h                - binmode
+ doio.c                - win9x can not rename a file when it is open
+ pp_sys.c              - do not define h_errno, init
+                         _pwent_struct.pw_comment
+ util.c                - use setenv
+ util.h                - PERL_FILE_IS_ABSOLUTE macro
+ pp.c                  - Comment about Posix vs IEEE math under
+                         Cygwin
+ perlio.c              - CR/LF mode
+ perliol.c             - Comment about EXTCONST under Cygwin
+
+=item Compiled Module Source
+
+ ext/Compress-Raw-Zlib/Makefile.PL
+                       - Can't install via CPAN shell under Cygwin
+ ext/Compress-Raw-Zlib/zlib-src/zutil.h
+                       - Cygwin is Unix-like and has vsnprintf
+ ext/Errno/Errno_pm.PL - Special handling for Win32 Perl under
+                         Cygwin
+ ext/POSIX/POSIX.xs    - tzname defined externally
+ ext/SDBM_File/sdbm/pair.c
+                       - EXTCONST needs to be redefined from
+                         EXTERN.h
+ ext/SDBM_File/sdbm/sdbm.c
+                       - binary open
+ ext/Sys/Syslog/Syslog.xs
+                       - Cygwin has syslog.h
+ ext/Sys/Syslog/win32/compile.pl
+                       - Convert paths to Windows paths
+ ext/Time-HiRes/HiRes.xs
+                       - Various timers not available
+ ext/Time-HiRes/Makefile.PL
+                       - Find w32api/windows.h
+ ext/Win32/Makefile.PL - Use various libraries under Cygwin
+ ext/Win32/Win32.xs    - Child dir and child env under Cygwin
+ ext/Win32API-File/File.xs
+                       - _open_osfhandle not implemented under
+                         Cygwin
+ ext/Win32CORE/Win32CORE.c
+                       - __declspec(dllexport)
+
+=item Perl Modules/Scripts
+
+ ext/B/t/OptreeCheck.pm - Comment about stderr/stdout order under
+                          Cygwin
+ ext/Digest-SHA/bin/shasum
+                       - Use binary mode under Cygwin
+ ext/Sys/Syslog/win32/Win32.pm
+                       - Convert paths to Windows paths
+ ext/Time-HiRes/HiRes.pm
+                       - Comment about various timers not available
+ ext/Win32API-File/File.pm
+                       - _open_osfhandle not implemented under
+                         Cygwin
+ ext/Win32CORE/Win32CORE.pm
+                       - History of Win32CORE under Cygwin
+ lib/Cwd.pm            - hook to internal Cwd::cwd
+ lib/ExtUtils/CBuilder/Platform/cygwin.pm
+                       - use gcc for ld, and link to libperl.dll.a
+ lib/ExtUtils/CBuilder.pm
+                       - Cygwin is Unix-like
+ lib/ExtUtils/Install.pm - Install and rename issues under Cygwin
+ lib/ExtUtils/MM.pm    - OS classifications
+ lib/ExtUtils/MM_Any.pm - Example for Cygwin
+ lib/ExtUtils/MakeMaker.pm
+                       - require MM_Cygwin.pm
+ lib/ExtUtils/MM_Cygwin.pm
+                       - canonpath, cflags, manifypods, perl_archive
+ lib/File/Fetch.pm     - Comment about quotes using a Cygwin example
+ lib/File/Find.pm      - on remote drives stat() always sets
+                         st_nlink to 1
+ lib/File/Spec/Cygwin.pm - case_tolerant
+ lib/File/Spec/Unix.pm - preserve //unc
+ lib/File/Spec/Win32.pm - References a message on cygwin.com
+ lib/File/Spec.pm      - Pulls in lib/File/Spec/Cygwin.pm
+ lib/File/Temp.pm      - no directory sticky bit
+ lib/Module/CoreList.pm - List of all module files and versions
+ lib/Net/Domain.pm     - No domainname command under Cygwin
+ lib/Net/Netrc.pm      - Bypass using stat() under Cygwin
+ lib/Net/Ping.pm       - ECONREFUSED is EAGAIN under Cygwin
+ lib/Pod/Find.pm       - Set 'pods' dir
+ lib/Pod/Perldoc/ToMan.pm - '-c' switch for pod2man
+ lib/Pod/Perldoc.pm    - Use 'less' pager, and use .exe extension
+ lib/Term/ANSIColor.pm - Cygwin terminal info
+ lib/perl5db.pl        - use stdin not /dev/tty
+ utils/perlbug.PL      - Add CYGWIN environment variable to report
+
+=item Perl Module Tests
+
+ dist/Cwd/t/cwd.t
+ ext/Compress-Zlib/t/14gzopen.t
+ ext/DB_File/t/db-btree.t
+ ext/DB_File/t/db-hash.t
+ ext/DB_File/t/db-recno.t
+ ext/DynaLoader/t/DynaLoader.t
+ ext/File-Glob/t/basic.t
+ ext/GDBM_File/t/gdbm.t
+ ext/POSIX/t/sysconf.t
+ ext/POSIX/t/time.t
+ ext/SDBM_File/t/sdbm.t
+ ext/Sys/Syslog/t/syslog.t
+ ext/Time-HiRes/t/HiRes.t
+ ext/Win32/t/Unicode.t
+ ext/Win32API-File/t/file.t
+ ext/Win32CORE/t/win32core.t
+ lib/AnyDBM_File.t
+ lib/Archive/Extract/t/01_Archive-Extract.t
+ lib/Archive/Tar/t/02_methods.t
+ lib/ExtUtils/t/Embed.t
+ lib/ExtUtils/t/eu_command.t
+ lib/ExtUtils/t/MM_Cygwin.t
+ lib/ExtUtils/t/MM_Unix.t
+ lib/File/Compare.t
+ lib/File/Copy.t
+ lib/File/Find/t/find.t
+ lib/File/Path.t
+ lib/File/Spec/t/crossplatform.t
+ lib/File/Spec/t/Spec.t
+ lib/Net/hostent.t
+ lib/Net/Ping/t/110_icmp_inst.t
+ lib/Net/Ping/t/500_ping_icmp.t
+ lib/Net/t/netrc.t
+ lib/Pod/Simple/t/perlcyg.pod
+ lib/Pod/Simple/t/perlcygo.txt
+ lib/Pod/Simple/t/perlfaq.pod
+ lib/Pod/Simple/t/perlfaqo.txt
+ lib/User/grent.t
+ lib/User/pwent.t
+
+=back
+
+=head1 BUGS ON CYGWIN
+
+Support for swapping real and effective user and group IDs is incomplete.
+On WinNT Cygwin provides C<setuid()>, C<seteuid()>, C<setgid()> and C<setegid()>.
+However, additional Cygwin calls for manipulating WinNT access tokens
+and security contexts are required.
+
+=head1 AUTHORS
+
+Charles Wilson <cwilson@ece.gatech.edu>,
+Eric Fifer <egf7@columbia.edu>,
+alexander smishlajev <als@turnhere.com>,
+Steven Morlock <newspost@morlock.net>,
+Sebastien Barre <Sebastien.Barre@utc.fr>,
+Teun Burgers <burgers@ecn.nl>,
+Gerrit P. Haase <gp@familiehaase.de>,
+Reini Urban <rurban@cpan.org>,
+Jan Dubois <jand@activestate.com>,
+Jerry D. Hedden <jdhedden@cpan.org>.
+
+=head1 HISTORY
+
+Last updated: 2012-02-08