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

       README.cygwin - Perl for Cygwin

       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 ver-
       sion(1,3,5) of Perl is provided in(1,8) the normal Cygwin install.  If you do not
       need to customize the configuration, consider using one of those pack-

       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:

       A recent net or commercial release of Cygwin is required.

       At the time(1,2,n) this document was last updated, Cygwin 1.5.2 was current.

       Cygwin Configuration

       While building Perl some changes may be necessary to your Cygwin setup(2,8)
       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(1,5) system (Win9x/WinME, WinNT/Win2K) or your
       Cygwin configuration (ntea, ntsec, binary/text mounts).  The only
       dependencies come from hard-coded pathnames like "/usr/local".  How-
       ever, your host(1,5) system and Cygwin configuration will affect Perl's run-
       time(1,2,n) behavior (see "TEST").

       * "PATH"
           Set the "PATH" environment variable so that Configure finds the
           Cygwin versions of programs.  Any 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(1,7) package), Con-
           figure will not prompt you to install man(1,5,7) pages.

       * Permissions
           On WinNT with either the ntea or ntsec "CYGWIN" settings, directory
           and file(1,n) permissions may not be set(7,n,1 builtins) correctly.  Since the build
           process creates directories and files, to be safe you may want to
           run a `"chmod(1,2) -R +w *"' on the entire Perl source tree.

           Also, it is a well known WinNT "feature" that files created by a
           login(1,3,5) that is a member of the Administrators group will be owned by
           the Administrators group.  Depending on your umask, you may find
           that you can not write(1,2) to files that you just created (because you
           are no longer the owner).  When using the ntsec "CYGWIN" setting,
           this is not an issue because it "corrects" the ownership to what
           you would expect on a UNIX system.

       The default options gathered by Configure with the assistance of
       hints/ will build a Perl that supports dynamic loading (which
       requires a shared libperl.dll).

       This will run Configure and keep a record:

         ./Configure 2>&1 | tee log.configure

       If you are willing to accept(2,8) 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,

         Any additional ld(1,8) flags (NOT including libraries)? [none] -s
         Any special flags to pass to gcc to use dynamic linking? [none] -s
         Any special flags to pass to ld2 to create a dynamically loaded library?
         [none] -s

       or you can edit hints/ and uncomment the relevant variables
       near the end of the file.

       Optional Libraries for Perl on Cygwin

       Several Perl functions and modules depend on the existence of some
       optional libraries.  Configure will find them if(3,n) they are installed in(1,8)
       one of the directories listed as being used for library searches.  Pre-
       built packages for most of these are available from the Cygwin

       * "-lcrypt"
           The crypt package distributed with Cygwin is a Linux compatible
           56-bit DES crypt port by Corinna Vinschen.

           Alternatively, the crypt libraries in(1,8) GNU libc have been ported to

           The DES based Ultra Fast Crypt port was done by Alexey Truhan:


           NOTE: There are various export restrictions on DES implementations,
           see the glibc README for more details.

           The MD5 port was done by Andy Piper:


       * "-lgdbm" ("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 parti-

       * "-lcygipc" ("use IPC::SysV")
           A port of SysV IPC is available for Cygwin.

           NOTE: This has not been extensively tested.  In particular, "d_sem-
           ctl_semun" is undefined because it fails a Configure test and on
           Win9x the shm*() functions seem to hang.  It also creates a compile
           time(1,2,n) dependency because perl.h includes <sys/ipc.h> and <sys/sem.h>
           (which will be required in(1,8) the future when compiling CPAN modules).

       * "-lutil"
           Included with the standard Cygwin netrelease is the inetutils pack-
           age 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(2,7,2 select_tut) an option when Con-
       figure prompts you or you can define (undefine) symbols on the command

       * "-Uusedl"
           Undefining this symbol forces Perl to be compiled statically.

       * "-Uusemymalloc"
           By default Perl uses the "malloc()" included with the Perl source.
           If you want to force Perl to build with the system "malloc()" unde-
           fine this symbol.

       * "-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(1,8) a C program and
           using more than one interpreter instance.  This works with the Cyg-
           win port.

       * "-Duse64bitint"
           By default Perl uses 32 bit integers.  If you want to use larger 64
           bit integers, define this symbol.

       * "-Duselongdouble"
           gcc supports long doubles (12 bytes).  However, several additional
           long double math functions are necessary to use them within Perl
           ({atan2, cos, exp, floor, fmod, frexp, isnan, log, modf, pow, sin,
           sqrt}l, strtold).  These are not yet available with Cygwin.

       * "-Dusethreads"
           POSIX threads are implemented in(1,8) Cygwin, define this symbol if(3,n) you
           want a threaded perl.

       * "-Duselargefiles"
           Cygwin uses 64-bit integers for internal size and position calcula-
           tions, this will be correctly detected and defined by Configure.

       * "-Dmksymlinks"
           Use this to build perl outside of the source tree.  This works with
           Cygwin.  Details can be found in(1,8) 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.

       * dlsym()
           ld2 is needed to build dynamic libraries, but it does not exist
           when "dlsym()" checking occurs (it is not created until `"make"'
           runs).  You will see the following message:

             Checking whether your C<dlsym()> needs a leading underscore ...
             ld2: not found
             I can't compile and run the test program.
             I'm guessing that dlsym doesn't need a leading underscore.

           Since the guess is correct, this is not a problem.

       * Win9x and "d_eofnblk"
           Win9x does not correctly report "EOF" with a non-blocking read(2,n,1 builtins) on a
           closed pipe.  You will see the following messages:

             But it also returns -1 to signal(2,7) 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 recom-
           mended value.

       * Compiler/Preprocessor defines
           The following error(8,n) occurs because of the Cygwin "#define" of

             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(8,n)" is reported instead of "missing binary

       Simply run make and wait:

         make 2>&1 | tee log.make

       Errors on Cygwin

       Errors like these are normal:

         make: [extra.pods] Error 1 (ignored)
         make: [extras.make] Error 1 (ignored)

       ld2 on Cygwin

       During `"make"', ld2 will be created and installed in(1,8) your $installbin
       directory (where you said to put public executables).  It does not wait
       until the `"make install"' process to install the ld2 script, this is
       because the remainder of the `"make"' refers to ld2 without fully spec-
       ifying its path and does this from multiple subdirectories.  The
       assumption is that $installbin is in(1,8) your current "PATH".  If this is
       not the case `"make"' will fail at some point.  If this happens, just
       manually copy ld2 from the source directory to somewhere in(1,8) your

       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"'.

       Test results vary depending on your host(1,5) system and your Cygwin config-
       uration.  If a test can pass in(1,8) some Cygwin setup(2,8), 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.

       File Permissions on Cygwin

       UNIX file(1,n) permissions are based on sets of mode bits for
       {read(2,n,1 builtins),write(1,2),execute} for each {user,group,other}.  By default Cygwin
       only tracks the Win32 read-only attribute represented as the UNIX file(1,n)
       user write(1,2) bit (files are always readable, files are executable if(3,n) they
       have a .{com,bat,exe} extension or begin with "#!", directories are
       always readable and executable).  On WinNT with the ntea "CYGWIN" set-
       ting, the additional mode bits are stored as extended file(1,n) attributes.
       On WinNT with the ntsec "CYGWIN" setting, permissions use the standard
       WinNT security descriptors and access(2,5) 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)

       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(3,n) 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 CYGWIN=ntsec), there should be no problems even if(3,n) perl
       was built on FAT.

       "fork()" failures in(1,8) io_* tests

       A "fork()" failure may result in(1,8) the following tests failing:


       See comment on fork in(1,8) Miscellaneous below.

       Script Portability on Cygwin

       Cygwin does an outstanding job of providing UNIX-like semantics on top
       of Win32 systems.  However, in(1,8) 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(1,8) the Cygwin docu-

       * Pathnames
           Cygwin pathnames can be separated by forward (/) or backward (\\)
           slashes.  They may also begin with drive letters (C:) or Universal
           Naming Codes (//UNC).  DOS device names (aux, con, prn, com*, lpt?,
           nul) are invalid as base filenames.  However, they can be used in(1,8)
           extensions (e.g., hello.aux).  Names may contain all printable
           characters except these:

             : * ? " < > |

           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).

       * Text/Binary
           When a file(1,n) is opened it is in(1,8) either text or binary mode.  In text
           mode a file(1,n) is subject to CR/LF/Ctrl-Z translations.  With Cygwin,
           the default mode for an "open(2,3,n)()" is determined by the mode of the
           mount(2,8) that underlies the file.  Perl provides a "binmode()" func-
           tion to set(7,n,1 builtins) binary mode 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(1,8)
           binary mode.

           The text/binary issue is covered at length in(1,8) the Cygwin documenta-

       * PerlIO
           PerlIO overrides the default Cygwin Text/Binary behaviour.  A file(1,n)
           will always treated as binary, regardless which mode of the mount(2,8)
           it lives on, just like it is in(1,8) UNIX.  So CR/LF translation needs
           to be requested in(1,8) either the "open(2,3,n)()" call like this:

             open(2,3,n)(FH, ">:crlf", "out.txt");

           which will do conversion from LF to CR/LF on the output, or in(1,8) the
           environment settings (add this to your .bashrc):

             export PERLIO=crlf

           which will pull in(1,8) the crlf PerlIO layer which does LF -> CRLF con-
           version(1,3,5) on every output generated by perl.

       * .exe
           The Cygwin "stat(1,2)()", "lstat()" and "readlink(1,2)()" 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(1,n) (e.g., cp in(1,8)
           a makefile) the .exe is not transparent.  The install included with
           Cygwin automatically appends a .exe when necessary.

       * "chown(1,2)()"
           On WinNT "chown(1,2)()" can change a file(1,n)'s user and group IDs.  On
           Win9x "chown(1,2)()" 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(1,2,n)()" an open(2,3,n) file(1,n) (although WinNT can).

           The Cygwin "chroot(1,2)()" implementation has holes (it can not restrict
           file(1,n) access(2,5) by native Win32 programs).

           Inplace editing "perl -i" of files doesn't work without doing a
           backup of the file(1,n) being edited "perl -i.bak" because of windowish
           restrictions, therefore Perl adds the suffix ".bak" automatically
           if(3,n) you use "perl -i" without specifying a backup extension.

           Using "fork()" after loading multiple dlls may fail with an inter-
           nal cygwin error(8,n) 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,n) 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(1,8) the Cygwin netrelease.  Use set-
           up.exe from to install it and run

       This will install Perl, including man(1,5,7) 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(1,2) access(2,5) to the directories in(1,8) question.

       Information on installing the Perl documentation in(1,8) HTML format can be
       found in(1,8) the INSTALL document.

       These are the files in(1,8) the Perl release that contain references to Cyg-
       win.  These very brief notes attempt to explain the reason for all con-
       ditional code.  Hopefully, keeping this up to date will allow the Cyg-
       win port to be kept as clean as possible (listing not updated yet).

             INSTALL README.cygwin README.win32 MANIFEST
             Changes Changes5.005 Changes5.004 Changes5.6
             pod/perl.pod pod/perlport.pod pod/perlfaq3.pod
             pod/perldelta.pod pod/perl5004delta.pod pod/perl56delta.pod
             pod/perlhist.pod pod/perlmodlib.pod perl/buildtoc pod/perltoc.pod

       Build, Configure, Make, Install
             Configure             - help finding hints from uname(1,2),
                                     shared libperl required for dynamic loading
             Makefile.SH           - linklibperl
             Porting/patchls       - cygwin in(1,8) port list
             installman            - man(1,5,7) pages with :: translated to .
             installperl           - install dll/ld2/perlld, install to pods
             makedepend.SH         - uwinfix

             t/io/tell.t           - binmode
             t/lib/b.t             - ignore Cwd from os_extras
             t/lib/glob-basic.t    - Win32 directory list access(2,5) differs from read(2,n,1 builtins) mode
             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(1,n)
                                     previously created and deleted), no -u (setuid)

       Compiled Perl Source
             EXTERN.h              - __declspec(dllimport)
             XSUB.h                - __declspec(dllexport)
             cygwin/cygwin.c       - os_extras (getcwd, spawn)
             perl.c                - os_extras
             perl.h                - binmode
             doio.c                - win9x can not rename(1,2,n) a file(1,n) when it is open(2,3,n)
             pp_sys.c              - do not define h_errno, pp_system with spawn
             util.c                - use setenv

       Compiled Module Source
             ext/POSIX/POSIX.xs    - tzname defined externally
                                   - EXTCONST needs to be redefined from EXTERN.h
                                   - binary open(2,3,n)

       Perl Modules/Scripts
             lib/            - hook to internal Cwd::cwd
                                   - require
                                   - canonpath, cflags, manifypods, perl_archive
             lib/File/      - on remote drives stat(1,2)() always sets st_nlink to 1
             lib/File/Spec/ - preserve //unc
             lib/File/      - no directory sticky bit
             lib/        - use stdin not /dev/tty(1,4)
             utils/perldoc.PL      - version(1,3,5) comment

       Support for swapping real and effective user and group IDs is incom-
       plete.  On WinNT Cygwin provides "setuid()", "seteuid()", "setgid()"
       and "setegid()".  However, additional Cygwin calls for manipulating
       WinNT access(2,5) tokens and security contexts are required.

       Charles Wilson <>, Eric Fifer
       <>, alexander smishlajev <>, Steven
       Morlock <>, Sebastien Barre
       <>, Teun Burgers <>, Gerrit P.
       Haase <>.

       Last updated: 2003-08-12

perl v5.8.5                       2004-04-23                     PERLCYGWIN(1)

References for this manual (incoming links)