perlcygwin

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

NAME
README.cygwin - 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 ver-
sion of Perl is provided in the normal Cygwin install. If you do not
need to customize the configuration, consider using one of those pack-
ages.

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 1.5.2 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 (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 system and Cygwin configuration will affect Perl's run-
time 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 package), Con-
figure will not prompt you to install man pages.

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

Also, it is a well known WinNT "feature" that files created by a
login 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 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.

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 libperl.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,

Any additional ld 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/cygwin.sh 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 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.

* "-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.

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

ftp://ftp.uni-erlangen.de/pub/pc/gnuwin32/cygwin/porters/Okhapkin_Sergey/cw32crypt-dist-0.tgz

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

The MD5 port was done by Andy Piper:

ftp://ftp.uni-erlangen.de/pub/pc/gnuwin32/cygwin/porters/Okhapkin_Sergey/libcrypt.tgz

* "-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-
tions.

* "-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 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 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 an option when Con-
figure prompts you or you can define (undefine) symbols on the command
line.

* "-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 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 Cygwin, define this symbol if 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 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 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 recom-
mended 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

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 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 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 your
"PATH".

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"'.

Test results vary depending on your host system and your Cygwin config-
uration. 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.

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 .{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 attributes.
On WinNT with the ntsec "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)

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 CYGWIN=ntsec), 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.

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 docu-
mentation.

* 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
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 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 "open()" is determined by the mode of the
mount that underlies the file. Perl provides a "binmode()" func-
tion to set 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
binary mode.

The text/binary issue is covered at length in the Cygwin documenta-
tion.

* PerlIO
PerlIO overrides the default Cygwin Text/Binary behaviour. A file
will always treated as binary, regardless which 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 con-
version 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 included with
Cygwin automatically appends a .exe when necessary.

* "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.

Using "fork()" after loading multiple dlls may fail with an inter-
nal 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 http://www.cygwin.com/setup.exe to install it and
run rebaseall.

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 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).

Documentation
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
cygwin/Makefile.SHs
cygwin/ld2.in
cygwin/perlld.in
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 - linklibperl
Porting/patchls - cygwin in port list
installman - man pages with :: translated to .
installperl - install dll/ld2/perlld, install to pods
makedepend.SH - uwinfix

Tests
t/io/tell.t - binmode
t/lib/b.t - ignore Cwd from os_extras
t/lib/glob-basic.t - Win32 directory list access differs from read 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
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 a file when it is open
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
ext/SDBM_File/sdbm/pair.c
- EXTCONST needs to be redefined from EXTERN.h
ext/SDBM_File/sdbm/sdbm.c
- binary open

Perl Modules/Scripts
lib/Cwd.pm - hook to internal Cwd::cwd
lib/ExtUtils/MakeMaker.pm
- require MM_Cygwin.pm
lib/ExtUtils/MM_Cygwin.pm
- canonpath, cflags, manifypods, perl_archive
lib/File/Find.pm - on remote drives stat() always sets st_nlink to 1
lib/File/Spec/Unix.pm - preserve //unc
lib/File/Temp.pm - no directory sticky bit
lib/perl5db.pl - use stdin not /dev/tty
utils/perldoc.PL - version comment

BUGS ON CYGWIN
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 tokens and security contexts are required.

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>.

HISTORY
Last updated: 2003-08-12

perl v5.8.6 2004-11-05 PERLCYGWIN(1)