perlcygwin.pod

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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> 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::winpid_to_pid()> 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 * 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.

Using C<fork()> after loading multiple dlls may fail with an internal cygwin
error like the following:

  C:\CYGWIN\BIN\PERL.EXE: *** couldn't allocate memory 0x10000(4128768) for 'C:\CYGWIN\LIB\PERL5\5.6.1\CYGWIN-MULTI\AUTO\SOCKET\SOCKET.DLL' alignment, Win32 error 8

    200 [main] perl 377147 sync_with_child: child -395691(0xB8) died before initialization with status code 0x1
   1370 [main] perl 377147 sync_with_child: *** child state child loading dlls

Use the rebase utility to resolve the conflicting dll addresses.  The
rebase package is included in the Cygwin netrelease.  Use setup.exe from
F<http://www.cygwin.com/setup.exe> to install it and run rebaseall.

=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.

=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
  Changes Changes5.004 Changes5.005 Changes5.6 Changes5.8
  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 pod.lst Porting/Glossary Porting/repository.pod
  Porting/checkAUTHORS.pl
  ext/Compress/Raw/Zlib/Changes ext/Compress/Raw/Zlib/README
  ext/Compress/Zlib/Changes ext/Cwd/Changes ext/DB_File/Changes
  ext/Encode/Changes ext/Sys/Syslog/Changes ext/Time/HiRes/Changes
  ext/Win32API/File/Changes lib/CGI/Changes lib/ExtUtils/CBuilder/Changes
  lib/ExtUtils/Changes lib/ExtUtils/NOTES lib/ExtUtils/PATCHING
  lib/ExtUtils/README lib/Module/Build/Changes 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/CGI.pm            - binmode and path separator
  lib/CPANPLUS/Dist/MM.pm - Commented out code that fails under Win32/Cygwin
  lib/CPANPLUS/Internals/Constants/Report.pm
                        - OS classifications
  lib/CPANPLUS/Internals/Constants.pm
                        - Contants for Cygwin
  lib/CPANPLUS/Internals/Report.pm
                        - Example of Cygwin report
  lib/CPANPLUS/Module.pm
                        - Abort if running on old Cygwin version
  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/Build/Compat.pm - Comment references 'make' under Cygwin
  lib/Module/Build/Platform/cygwin.pm
                        - Use '.' for man page separator
  lib/Module/Build.pm   - Cygwin is Unix-like
  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

  ext/Compress/Zlib/t/14gzopen.t
  ext/Cwd/t/cwd.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/CPANPLUS/t/05_CPANPLUS-Internals-Fetch.t
  lib/CPANPLUS/t/20_CPANPLUS-Dist-MM.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/Module/Build/t/destinations.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 <[e-mail]>,
Eric Fifer <[e-mail]>,
alexander smishlajev <[e-mail]>,
Steven Morlock <[e-mail]>,
Sebastien Barre <[e-mail]>,
Teun Burgers <[e-mail]>,
Gerrit P. Haase <[e-mail]>,
Reini Urban <[e-mail]>,
Jan Dubois <[e-mail]>,
Jerry D. Hedden <[e-mail]>.

=head1 HISTORY

Last updated: 2007-09-25