perlcygo.txt

source of perl for linux application,

Hard Links
FAT partitions do not support hard links (whereas NTFS does), in which case Cygwin implements link() by copying the file. On remote (network) drives Cygwin's stat() always sets st_nlink to 1, so the link count for remote directories and files is not available. In either case, these tests will fail:
  Failed Test           List of failed
  ------------------------------------
  io/fs.t               4
  op/stat.t             3
Filetime Granularity
On FAT partitions the filetime granularity is 2 seconds. The following test will fail:
  Failed Test           List of failed
  ------------------------------------
  io/fs.t               18
Tainting Checks
When Perl is running in taint mode, $ENV{PATH} is considered tainted and not used, so DLLs not in the default system directories will not be found. While the tests are running you will see warnings popup from the system with messages like:
  Win9x
    Error Starting Program
    A required .DLL file, CYGWIN1.DLL, was not found
  WinNT
    perl.exe - Unable to Locate DLL
    The dynamic link library cygwin1.dll could not be found in the
      specified path ...
Just click OK and ignore them. When running `make test', 2 popups occur. During `./perl harness', 4 popups occur. Also, these tests will fail:
  Failed Test           List of failed
  ------------------------------------
  op/taint.t            1, 3, 31, 37
Alternatively, you can copy cygwin1.dll into the directory where the tests run:
  cp /bin/cygwin1.dll t
or one of the Windows system directories (although, this is not recommended).
/etc/group
Cygwin does not require /etc/group, in which case the op/grent.t test will be skipped. The check performed by op/grent.t expects to see entries that use the members field, otherwise this test will fail:
  Failed Test           List of failed
  ------------------------------------
  op/grent.t            1
Script Portability
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 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() 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.
.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).
INSTALL
This will install Perl, including man pages.
  make install | 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
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
  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 pod/buildtoc.PL 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
When make starts, it warns about overriding commands for perlmain.o.
`make clean' does not remove library .def or .exe.stackdump files.
The ld2 script contains references to the source directory. You should change these to $installbin after `make install'.
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.
When building DLLs, `dllwrap --export-all-symbols' is used to export global symbols. It might be better to generate an explicit .def file (see makedef.pl). Also, DLLs can now be build with `gcc -shared'.
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]>.
HISTORY
Last updated: 9 November 2000