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PERLCYGWIN(1) Perl Programmers Reference Guide PERLCYGWIN(1)

NAME
perlcygwin - Perl for Cygwin

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.

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.

PREREQUISITES FOR COMPILING PERL ON CYGWIN
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:

<http://www.cygwin.com/>

A recent net or commercial release of Cygwin is required.

At the time this document was last updated, Cygwin 1.7.10 was current.

Cygwin Configuration
While building Perl some changes may be necessary to your Cygwin setup so that Perl builds cleanly. These
changes are not required for normal Perl usage.

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 "/usr/local". However, your host system and Cygwin configuration will affect
Perl's runtime behavior (see "TEST").

· "PATH"

Set the "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 "PATH".

· nroff

If you do not have nroff (which is part of the groff package), Configure will not prompt you to install
man pages.

CONFIGURE PERL ON CYGWIN
The default options gathered by Configure with the assistance of hints/cygwin.sh will build a Perl that
supports dynamic loading (which requires a shared 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 -de. However, several useful customizations
are available.

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 -s option when Configure
prompts you,

· "-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.

· "-lgdbm_compat" ("use GDBM_File")

GDBM is available for Cygwin.

NOTE: The GDBM library only works on NTFS partitions.

· "-ldb" ("use DB_File")

BerkeleyDB is available for Cygwin.

NOTE: The BerkeleyDB library only completely works on NTFS partitions.

· "cygserver" ("use IPC::SysV")

A port of SysV IPC is available for Cygwin.

NOTE: This has not been extensively tested. In particular, "d_semctl_semun" is undefined because it fails
a Configure test and on Win9x the shm*() functions seem to hang. It also creates a compile time
dependency because perl.h includes <sys/ipc.h> and <sys/sem.h> (which will be required in the future when
compiling CPAN modules). CURRENTLY NOT SUPPORTED!

· "-lutil"

Included with the standard Cygwin netrelease is the inetutils package which includes libutil.a.

Configure-time Options for Perl on Cygwin
The 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.

· "-Uusedl"

Undefining this symbol forces Perl to be compiled statically.

· "-Dusemymalloc"

By default Perl does not use the "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.

· "-Uuseperlio"

Undefining this symbol disables the PerlIO abstraction. PerlIO is now the default; it is not recommended
to disable PerlIO.

· "-Dusemultiplicity"

Multiplicity is required when embedding Perl in a C program and using more than one interpreter instance.

· "-Uuseithreads"

Define this symbol if you want not-threaded faster perl.

· "-Duselargefiles"

Cygwin uses 64-bit integers for internal size and position calculations, this will be correctly detected
and defined by Configure.

· "-Dmksymlinks"

Use this to build perl outside of the source tree. Details can be found in the INSTALL document. This is
the recommended way to build perl from sources.

Suspicious Warnings on Cygwin
You may see some messages during Configure that seem suspicious.

· Win9x and "d_eofnblk"

Win9x does not correctly report "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.

· Compiler/Preprocessor defines

The following error occurs because of the Cygwin "#define" of "_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".

MAKE ON CYGWIN
Simply run make and wait:

make 2>&1 | tee log.make

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 "./perl harness".
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)

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.

"fork()" failures in io_* tests
A "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 "Miscellaneous" below.

Specific features of the Cygwin port
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.

· Pathnames

Cygwin pathnames are separated by forward (/) slashes, Universal Naming Codes (//UNC) are also supported
Since cygwin-1.7 non-POSIX pathnames are disencouraged. 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.
on files that otherwise would be treated as text. "sysopen()" with the "O_TEXT" flag sets text mode on
files that otherwise would be treated as binary:

sysopen(FOO, "bar", O_WRONLY|O_CREAT|O_TEXT)

"lseek()", "tell()" and "sysseek()" only work with files opened in binary mode.

The text/binary issue is covered at length in the Cygwin documentation.

· 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 "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.

· .exe

The Cygwin "stat()", "lstat()" and "readlink()" functions make the .exe extension transparent by looking
for foo.exe when you ask for foo (unless a foo also exists). Cygwin does not require a .exe extension,
but gcc adds it automatically when building a program. However, when accessing an executable as a normal
file (e.g., cp in a makefile) the .exe is not transparent. The install program included with Cygwin
automatically appends a .exe when necessary.

· 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. $$ is the cygwin pid of /usr/bin/perl, which is not the winpid. Use "Cygwin::winpid_to_pid()" and
"Cygwin::winpid_to_pid()" to translate between them.

· Cygwin vs. Windows errors

Under Cygwin, $^E is the same as $!. When using Win32 API Functions, use "Win32::GetLastError()" to get
the last Windows error.

· rebase errors on fork or system

Using "fork()" or "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:

2. kill all cygwin processes and services, start dash from cmd.exe and run "rebaseall".

· "chown()"

On WinNT "chown()" can change a file's user and group IDs. On Win9x "chown()" is a no-op, although this
is appropriate since there is no security model.

· Miscellaneous

File locking using the "F_GETLK" command to "fcntl()" is a stub that returns "ENOSYS".

Win9x can not "rename()" an open file (although WinNT can).

The Cygwin "chroot()" implementation has holes (it can not restrict file access by native Win32 programs).

Inplace editing "perl -i" of files doesn't work without doing a backup of the file being edited "perl
-i.bak" because of windowish restrictions, therefore Perl adds the suffix ".bak" automatically if you use
"perl -i" without specifying a backup extension.

Prebuilt methods:
"Cwd::cwd"
Returns the current working directory.

"Cygwin::pid_to_winpid"
Translates a cygwin pid to the corresponding Windows pid (which may or may not be the same).

"Cygwin::winpid_to_pid"
Translates a Windows pid to the corresponding cygwin pid (if any).

"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.

"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.

"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

"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".

binmode,cygdrive,/cygdrive

"Cygwin::is_binmount"
Returns true if the given cygwin path is binary mounted, false if the path is mounted in textmode.

"Cygwin::sync_winenv"
Cygwin does not initialize all original Win32 environment variables. See the bottom of this page
http://cygwin.com/cygwin-ug-net/setup-env.html <http://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.

INSTALL PERL ON CYGWIN
This will install Perl, including man pages.

make install 2>&1 | tee log.make-install

NOTE: If "STDERR" is redirected "make install" will not prompt you to install perl into /usr/bin.

You may need to be Administrator to run "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 INSTALL document.

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.

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
ext/Compress-Raw-Zlib/README ext/Compress-Zlib/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

Build, Configure, Make, Install
cygwin/Makefile.SHs
ext/IPC/SysV/hints/cygwin.pl
ext/NDBM_File/hints/cygwin.pl
NetWare/Makefile
plan9/mkfile
symbian/sanity.pl symbian/sisify.pl
hints/uwin.sh
vms/descrip_mms.template
win32/Makefile win32/makefile.mk

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()

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

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/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
- Constants 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

Perl Module Tests
dist/Cwd/t/cwd.t
ext/Compress-Zlib/t/14gzopen.t
ext/DB_File/t/db-btree.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

BUGS ON CYGWIN
Support for swapping real and effective user and group IDs is incomplete. On WinNT Cygwin provides
"setuid()", "seteuid()", "setgid()" and "setegid()". However, additional Cygwin calls for manipulating WinNT
access tokens and security contexts are required.

AUTHORS
Charles Wilson <[email protected]>, Eric Fifer <[email protected]>, alexander smishlajev
<[email protected]>, Steven Morlock <[email protected]>, Sebastien Barre <[email protected]>, Teun
Burgers <[email protected]>, Gerrit P. Haase <[email protected]>, Reini Urban <[email protected]>, Jan Dubois
<[email protected]>, Jerry D. Hedden <[email protected]>.

HISTORY
Last updated: 2012-02-08

perl v5.16.3 2013-03-04 PERLCYGWIN(1)