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.
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:
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.
However, your host system and Cygwin configuration will affect Perl's
runtime behavior (see TEST).
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.
On WinNT with either the ntea or ntsecCYGWIN 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 ntsecCYGWIN 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/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.
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.
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.
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!
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.
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.
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.
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.
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 specifying 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.
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
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.
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 nteaCYGWIN
setting, the additional mode bits are stored as extended file attributes.
On WinNT with the ntsecCYGWIN 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)
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.
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.
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).
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() function 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 documentation.
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 conversion
on every output generated by perl.
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.
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.
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 internal cygwin
error like the following:
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.
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 (listing not updated yet).
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
EXTERN.h - __declspec(dllimport)
XSUB.h - __declspec(dllexport)
cygwin/cygwin.c - os_extras (getcwd, spawn, Cygwin::winpid_to_pid,
Cygwin::pid_to_winpid)
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
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
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.
