newlib/winsup/doc/new-features.sgml

<sect1 id="ov-new1.7"><title>What's new and what changed in Cygwin 1.7</title>

<sect2 id="ov-new1.7.7"><title>What's new and what changed from 1.7.6 to 1.7.7</title>

<itemizedlist mark="bullet">

<listitem><para>
Partially revert the 1.7.6 change to set the Win32 current working directory
(CWD) always to an invalid directory, since it breaks backward compatibility
too much.  The Cygwin CWD and the Win32 CWD are now kept in sync again, unless
the Cygwin CWD is not usable as Win32 CWD.  See the reworked
<xref linkend="pathnames-win32-api"></xref> for details.
</para></listitem>

<listitem><para>
Make sure to follow the Microsoft security advisory concerning DLL hijacking.
See the <ulink url="http://www.microsoft.com/technet/security/advisory/2269637.mspx">Microsoft Security Advisory (2269637) "Insecure Library Loading Could Allow Remote Code Execution"</ulink> for details.
</para></listitem>

<listitem><para>
Allow to link against -lbinmode instead of /lib/binmode.o.  Same for
-ltextmode, -ltextreadmode and -lautomode. 
See <xref linkend="textbin-devel"></xref> for details.
</para></listitem>

</itemizedlist>

</sect2>

<sect2 id="ov-new1.7.6"><title>What's new and what changed from 1.7.5 to 1.7.6</title>

<itemizedlist mark="bullet">

<listitem><para>
Add new mount options "dos" and "ihash" to allow overriding Cygwin default
behaviour on broken filesystems not recognized by Cygwin.
</para></listitem>

<listitem><para>
Add new mount option "bind" to allow remounting parts of the POSIX file
hirarchy somewhere else.
</para></listitem>

<listitem><para>
Ttys and ptys are handled as securable objects using file-like permissions
and owner/group information.  <command>chmod</command> and
<command>chown</command> now work on ttys/ptys.  A new mechanism is used
to propagate pty handles safely to other processes, which does not require
to use Cygserver.
</para></listitem>

<listitem><para>
Pass on coresize settings made with setrlimit(2).  This allows shells to
disable creating stackdump files in child processes via
<screen>ulimit -c 0</screen> in bash or <screen>limit coredumpsize 0</screen>
in tcsh.
</para></listitem>

<listitem><para>
Locale categories contain all localization strings additionally as wide-char
strings.  locale(1) prints these values just as on Linux.  nl_langinfo(3)
allows to fetch them.
</para></listitem>

<listitem><para>
New interfaces mkostemp(3) and mkostemps(3) are added.
</para></listitem>

<listitem><para>
New virtual file /proc/filesystems.
</para></listitem>

<listitem><para>
clock_gettime(3) and clock_getres(3) accept CLOCK_MONOTONIC.
</para></listitem>

<listitem><para>
DEPRECATED with 1.7.7: Cygwin handles the current working directory entirely
on its own.  The Win32 current working directory is set to an invalid path to
be out of the way.  [...]
</para></listitem>

</itemizedlist>

</sect2>

<sect2 id="ov-new1.7.5"><title>What's new and what changed from 1.7.3 to 1.7.5</title>

<itemizedlist mark="bullet">

<listitem><para>
Support for DEC Backarrow Key Mode escape sequences (ESC [ ? 67 h, ESC [ ? 67 l)
in Windows console.
</para></listitem>

</itemizedlist>

</sect2>

<sect2 id="ov-new1.7.3"><title>What's new and what changed from 1.7.2 to 1.7.3</title>

<itemizedlist mark="bullet">

<listitem><para>
Support for GB2312/EUC-CN.  These charsets are implemented as aliases to GBK.
GB2312 is now the default charset name for the locales zh_CN and zh_SG, just
as on Linux.
</para></listitem>

<listitem><para>
Modification and access timestamps of devices reflect the current time.
</para></listitem>

</itemizedlist>

</sect2>

<sect2 id="ov-new1.7.2"><title>What's new and what changed from 1.7.1 to 1.7.2</title>

<itemizedlist mark="bullet">

<listitem><para>Localization support has been much improved.</para>

  <itemizedlist mark="bullet">

  <listitem><para>
  Cygwin now handles locales using the underlying Windows locale
  support.  The locale must exist in Windows to be recognized.
  Locale aliases from the file /usr/share/locale/locale.alias are also
  allowed, as long as their replacement is supported by the underlying Windows.
  </para></listitem>

  <listitem><para>
  New tool "locale" to fetch locale information and default locales based on
  the Windows default settings as well as lists of all supported locales
  and character sets.
  </para></listitem>

  <listitem><para>
  Default charset for locales without explicit charset is now chosen
  from a list of Linux-compatible charsets.
  </para>
  
  <para>
  For instance: en_US -> ISO-8859-1, ja_JP -> EUC-JP, zh_TW -> Big5.
  </para></listitem>

  <listitem><para>
  Added support for the charsets GEORGIAN-PS, PT154, and TIS-620.
  </para></listitem>

  <listitem><para>
  Support for the various locale modifiers to switch charsets as on Linux.
  </para></listitem>

  <listitem><para>
  Default charset in the "C" or "POSIX" locale has been changed back
  from UTF-8 to ASCII, to avoid problems with applications
  expecting a singlebyte charset in the "C"/"POSIX" locale.  Still use
  UTF-8 internally for filename conversion in this case.
  </para></listitem>

  <listitem><para>
  LC_COLLATE, LC_MONETARY, LC_NUMERIC, and LC_TIME localization is
  enabled via Windows locale support.  LC_MESSAGES is enabled via a big
  table with localized strings.
  </para></listitem>

  <listitem><para>
  fnmatch(3), regcomp(3), regexec(3) calls are now multibyte-aware.
  </para></listitem>

  <listitem><para>
  printf(3), wprintf(3) families of functions now handle the grouping
  flag, the apostrophe <literal>'</literal>, per POSIX-1.2008.  The
  integer portion of the result of a decimal conversion (%i, %d, %u, %f,
  %F, %g, %G) will be formatted with thousands' grouping characters.
  </para></listitem>

  <listitem><para>
  strftime(3), wcsftime(3), and strptime(3) now handle the E and O format
  modifiers to print/scan alternative date and time representations or to
  use alternative digits in locales which support this.  Additionally these
  functions now also support the padding modifiers '0' and '+', as well as
  a field width per POSIX-1.2008.
  </para></listitem>

  <listitem><para>
  New strfmon(3) call.
  </para></listitem>

  </itemizedlist>

</listitem>

<listitem><para>
Support open(2) flags O_CLOEXEC and O_TTY_INIT flags.  Support fcntl
flag F_DUPFD_CLOEXEC.  Support socket flags SOCK_CLOEXEC and SOCK_NONBLOCK.
Add new Linux-compatible API calls accept4(2), dup3(2), and pipe2(2).
Support the signal SIGPWR.
</para></listitem>

<listitem><para>Enhanced Windows console support.</para>

  <itemizedlist mark="bullet">

  <listitem><para>
  The console's backspace keycode can be changed using 'stty erase'.
  </para></listitem>

  <listitem><para>
  Function keys send distinguished escape sequences compatible with rxvt.
  Keypad keys send distinguished escape sequences, xterm-style.
  </para></listitem>

  <listitem><para>
  Support of combining Alt and AltGr modifiers in console window
  (compatible with xterm and mintty), so that e.g. Alt-@ sends ESC @
  also on keyboards where @ is mapped to an AltGr combination.
  </para></listitem>

  <listitem><para>
  Report mouse wheel scroll events in mouse reporting mode 1000 (note:
  this doesn't seem to work on all systems, assumedly due to driver
  interworking issues).
  Add mouse reporting mode 1002 to report mouse drag movement.
  Add mouse reporting mode 1003 to report any mouse movement.
  Add focus event reporting (mode 1004), compatible with xterm and mintty.
  </para></listitem>

  <listitem><para>
  Add escape sequences for not bold (22), not invisible (28), not
  blinking (25) (compatible with xterm and mintty).
  </para></listitem>

  <listitem><para>
  Support VT100 line drawing graphics mode in console window (compatible
  with xterm and mintty).
  </para></listitem>

  </itemizedlist>

</listitem>

<listitem><para>
Handle native DOS paths always as if mounted with "posix=0,noacl".
</para></listitem>

<listitem><para>
Handle UNC paths starting with slashes identical to /cygdrive paths.
In other words, use the /cygdrive mount flags for these paths as well.
</para></listitem>

<listitem><para>
Recognize NWFS filesystem and workaround broken OS call.
</para></listitem>

<listitem><para>
New support for eXtensible Data Record (XDR) encoding and decoding,
as defined by RFCs 1014, 1832, and 4506.  The XDR protocol and
functions are useful for cross-platfrom data exchange, and are
commonly used as the core data interchange format for Remote
Procedure Call (RPC) and NFS.
</para></listitem>

</itemizedlist>

</sect2>

<sect2 id="ov-new1.7-os"><title>OS related changes</title>

<itemizedlist mark="bullet">

<listitem><para>
Windows 95, 98 and Me are not supported anymore.  The new Cygwin 1.7 DLL
will not run on any of these systems.
</para></listitem>

<listitem><para>
Add support for Windows 7 and Windows Server 2008 R2.
</para></listitem>

</itemizedlist>

</sect2>

<sect2 id="ov-new1.7-file"><title>File Access related changes</title>

<itemizedlist mark="bullet">

<listitem><para>
Mount points are no longer stored in the registry.  Use /etc/fstab and
/etc/fstab.d/$USER instead.  Mount points created with mount(1) are only
local to the current session and disappear when the last Cygwin process
in the session exits.
</para></listitem>

<listitem><para>
Cygwin creates the mount points for /, /usr/bin, and /usr/lib
automatically from it's own position on the disk.  They don't have to be
specified in /etc/fstab.
</para></listitem>

<listitem><para>
If a filename cannot be represented in the current character set, the
character will be converted to a sequence Ctrl-X + UTF-8 representation
of the character.  This allows to access all files, even those not
having a valid representation of their filename in the current character
set.  To always have a valid string, use the UTF-8 charset by
setting the environment variable $LANG, $LC_ALL, or $LC_CTYPE to a valid
POSIX value, for instance in Cygwin.bat like this:
</para>

<screen>
set LC_CTYPE=en_US.UTF-8
</screen>

</listitem>

<listitem><para>
PATH_MAX is now 4096.  Internally, path names can be as long as the
underlying OS can handle (32K).
</para></listitem>

<listitem><para>
struct dirent now supports d_type, filled out with DT_REG or DT_DIR.
All other file types return as DT_UNKNOWN for performance reasons.
</para></listitem>

<listitem><para>
The CYGWIN environment variable options "ntsec" and "smbntsec" have been
replaced by the per-mount option "acl"/"noacl".
</para></listitem>

<listitem><para>
The CYGWIN environment variable option "ntea" has been removed without
substitute.
</para></listitem>

<listitem><para>
The CYGWIN environment variable option "check_case" has been removed in
favor of real case-sensitivity on file systems supporting it.
</para></listitem>

<listitem><para>
Creating filenames with special DOS characters '"', '*', ':', '&lt;',
'&gt;', '|' is supported.
</para></listitem>

<listitem><para>
Creating files with special DOS device filename components ("aux",
"nul", "prn") is supported.
</para></listitem>

<listitem><para>
File names are case sensitive if the OS and the underlying file system
supports it.  Works on NTFS and NFS.  Does not work on FAT and Samba
shares.  Requires to change a registry key (see the User's Guide).  Can
be switched off on a per-mount basis.
</para></listitem>

<listitem><para>
Due to the above changes, managed mounts have been removed.
</para></listitem>

<listitem><para>
Incoming DOS paths are always handled case-insensitive and get no POSIX
permission, as if they are mounted with noacl,posix=0 mount flags.
</para></listitem>

<listitem><para>
unlink(2) and rmdir(2) try very hard to remove files/directories even if
they are currently accessed or locked.  This is done by utilizing the
hidden recycle bin directories and marking the files for deletion.
</para></listitem>

<listitem><para>
rename(2) rewritten to be more POSIX conformant.
</para></listitem>

<listitem><para>
access(2) now performs checks using the real user ID, as required by
POSIX; the old behavior of querying based on effective user ID is
available through the new faccessat(2) and euidaccess(2) APIs.
</para></listitem>

<listitem><para>
Add st_birthtim member to struct stat.
</para></listitem>

<listitem><para>
File locking is now advisory, not mandatory anymore.  The fcntl(2) and
the new lockf(2) APIs create and maintain locks with POSIX semantics,
the flock(2) API creates and maintains locks with BSD semantics.  POSIX
and BSD locks are independent of each other.
</para></listitem>

<listitem><para>
Implement atomic O_APPEND mode.
</para></listitem>

<listitem><para>
New open(2) flags O_DIRECTORY, O_EXEC and O_SEARCH.
</para></listitem>

<listitem><para>
Make the "plain file with SYSTEM attribute set" style symlink default
again when creating symlinks.  Only create Windows shortcut style
symlinks if CYGWIN=winsymlinks is set in the environment.
</para></listitem>

<listitem><para>
Symlinks now use UTF-16 encoding for the target filename for better
internationalization support.  Cygwin 1.7 can read all old style
symlinks, but the new style is not compatible with older Cygwin
releases.
</para></listitem>

<listitem><para>
Handle NTFS native symlinks available since Vista/2008 as symlinks (but
don't create Vista/2008 symlinks due to unfortunate OS restrictions).
</para></listitem>

<listitem><para>
Recognize NFS shares and handle them using native mechanisms.  Recognize
and create real symlinks on NFS shares.  Get correct stat(2) information
and set real mode bits on open(2), mkdir(2) and chmod(2).
</para></listitem>

<listitem><para>
Recognize MVFS and workaround problems manipulating metadata and handling
DOS attributes.
</para></listitem>

<listitem><para>
Recognize Netapp DataOnTap drives and fix inode number handling.
</para></listitem>

<listitem><para>
Recognize Samba version beginning with Samba 3.0.28a using the new
extended version information negotiated with the Samba developers.
</para></listitem>

<listitem><para>
Stop faking hardlinks by copying the file on filesystems which don't
support hardlinks natively (FAT, FAT32, etc.).  Just return an error
instead, just like Linux.
</para></listitem>

<listitem><para>
List servers of all accessible domains and workgroups in // instead of
just the servers in the own domain/workgroup.
</para></listitem>

<listitem><para>
Support Linux-like extended attributes ([fl]getxattr, [fl]listxattr,
[fl]setxattr, [fl]removexattr).
</para></listitem>

<listitem><para>
New file conversion API for conversion from Win32 to POSIX path and vice
versa (cygwin_conv_path, cygwin_create_path, cygwin_conv_path_list).
</para></listitem>

<listitem><para>
New openat family of functions: openat, faccessat, fchmodat, fchownat,
fstatat, futimesat, linkat, mkdirat, mkfifoat, mknodat, readlinkat,
renameat, symlinkat, unlinkat.
</para></listitem>

<listitem><para>
Other new APIs: posix_fadvise, posix_fallocate, funopen, fopencookie,
open_memstream, open_wmemstream, fmemopen, fdopendir, fpurge, mkstemps,
eaccess, euidaccess, canonicalize_file_name, fexecve, execvpe.
</para></listitem>

</itemizedlist>

</sect2>

<sect2 id="ov-new1.7-net"><title>Network related changes</title>

<itemizedlist mark="bullet">

<listitem><para>
New implementation for blocking sockets and select on sockets which is
supposed to allow POSIX-compatible sharing of sockets between threads
and processes.
</para></listitem>

<listitem><para>
send/sendto/sendmsg now send data in 64K chunks to circumvent an
internal buffer problem in WinSock (KB 201213).
</para></listitem>

<listitem><para>
New send/recv option MSG_DONTWAIT.
</para></listitem>

<listitem><para>
IPv6 support.  New APIs getaddrinfo, getnameinfo, freeaddrinfo,
gai_strerror, in6addr_any, in6addr_loopback.  On IPv6-less systems,
replacement functions are available for IPv4.  On systems with IPv6
enabled, the underlying WinSock functions are used.  While I tried hard
to get the functionality as POSIXy as possible, keep in mind that a
*fully* conformant implementation of getaddrinfo and other stuff is only
available starting with Windows Vista/2008.
</para></listitem>

<listitem><para>
Resolver functions (res_init, res_query, res_search, res_querydomain,
res_mkquery, res_send, dn_comp, dn_expand) are now part of Cygwin.
Applications don't have to link against minires anymore.  Actually, this
*is* the former libminires.a.
</para></listitem>

<listitem><para>
rcmd is now implemented inside of Cygwin, instead of calling the WinSock
function.  This allows rsh(1) usage on Vista/2008 and later, which
dropped this function from WinSock.
</para></listitem>

<listitem><para>
Define multicast structures in netinet/in.h.  Note that fully conformant
multicast support is only available beginning with Vista/2008.
</para></listitem>

<listitem><para>
Improve get_ifconf.  Redefine struct ifreq and subsequent datastructures
to be able to keep more information.  Support SIOCGIFINDEX,
SIOCGIFDSTADDR and the Cygwin specific SIOCGIFFRNDLYNAM.  Support real
interface flags on systems supporting them.
</para></listitem>

<listitem><para>
Other new APIs: bindresvport, bindresvport_sa, gethostbyname2,
iruserok_sa, rcmd_af, rresvport_af.  getifaddrs, freeifaddrs,
if_nametoindex, if_indextoname, if_nameindex, if_freenameindex.
</para></listitem>

<listitem><para>
Add /proc/net/if_inet6.
</para></listitem>

</itemizedlist>

</sect2>

<sect2 id="ov-new1.7-device"><title>Device related changes</title>

<itemizedlist mark="bullet">

<listitem><para>
Reworked pipe implementation which uses overlapped IO to create more
reliable interruptible pipes and fifos.
</para></listitem>

<listitem><para>
The CYGWIN environment variable option "binmode" has been removed.
</para></listitem>

<listitem><para>
Improved fifo handling by using native Windows named pipes.
</para></listitem>

<listitem><para>
Detect when a stdin/stdout which looks like a pipe is really a tty.
Among other things, this allows a debugged application to recognize that
it is using the same tty as the debugger.
</para></listitem>

<listitem><para>
Support UTF-8 in console window.
</para></listitem>

<listitem><para>
In the console window the backspace key now emits DEL (0x7f) instead of
BS (0x08), Alt-Backspace emits ESC-DEL (0x1b,0x7f) instead of DEL
(0x7f), same as the Linux console and xterm.  Control-Space now emits an
ASCII NUL (0x0) character.
</para></listitem>

<listitem><para>
Support up to 64 serial interfaces using /dev/ttyS0 - /dev/ttyS63.
</para></listitem>

<listitem><para>
Support up to 128 raw disk drives /dev/sda - /dev/sddx.
</para></listitem>

<listitem><para>
New API: cfmakeraw, get_avphys_pages, get_nprocs, get_nprocs_conf,
get_phys_pages, posix_openpt.
</para></listitem>

</itemizedlist>

</sect2>

<sect2 id="ov-new1.7-posix"><title>Other POSIX related changes</title>

<itemizedlist mark="bullet">

<listitem><para>
A lot of character sets are supported now via a call to setlocale().
The setting of the environment variables $LANG, $LC_ALL or $LC_CTYPE
will be used.  For instance, setting $LANG to "de_DE.ISO-8859-15" before
starting a Cygwin session will use the ISO-8859-15 character set in the
entire session.  The default locale in the absence of one of the
aforementioned environment variables is "C.UTF-8".
</para>

<para>
The full list of supported character sets: "ASCII", "ISO-8859-x" with x
in 1-16, except 12, "UTF-8", Windows codepages "CPxxx", with xxx in
(437, 720, 737, 775, 850, 852, 855, 857, 858, 862, 866, 874, 1125, 1250,
1251, 1252, 1253, 1254, 1255, 1256, 1257, 1258), "KOI8-R", "KOI8-U",
"SJIS", "GBK", "eucJP", "eucKR", and "Big5".
</para>

</listitem>

<listitem><para>
Allow multiple concurrent read locks per thread for pthread_rwlock_t.
</para></listitem>

<listitem><para>
Implement pthread_kill(thread, 0) as per POSIX.
</para></listitem>

<listitem><para>
New API for POSIX IPC: Named semaphores: sem_open, sem_close,
sem_unlink.  Message queues: mq_open, mq_getattr, mq_setattr, mq_notify,
mq_send, mq_timedsend, mq_receive, mq_timedreceive, mq_close, mq_unlink.
Shared memory: shm_open, shm_unlink.
</para></listitem>

<listitem><para>
Only declare expected functions in &lt;strings.h&gt;, don't include
&lt;string.h&gt; from here.
</para></listitem>

<listitem><para>
Support for WCONTINUED, WIFCONTINUED() added to waitpid and wait4.
</para></listitem>

<listitem><para>
New APIs: _Exit, confstr, insque, remque, sys_sigabbrev, posix_madvise,
posix_memalign, reallocf, exp10, exp10f, pow10, pow10f, lrint, lrintf,
rint, rintf, llrint, llrintf, llrintl, lrintl, rintl, mbsnrtowcs,
strcasestr, stpcpy, stpncpy, wcpcpy, wcpncpy, wcsnlen, wcsnrtombs,
wcsftime, wcstod, wcstof, wcstoimax, wcstok, wcstol, wcstoll, wcstoul,
wcstoull, wcstoumax, wcsxfrm, wcscasecmp, wcsncasecmp, fgetwc, fgetws,
fputwc, fputws, fwide, getwc, getwchar, putwc, putwchar, ungetwc,
asnprintf, dprintf, vasnprintf, vdprintf, wprintf, fwprintf, swprintf,
vwprintf, vfwprintf, vswprintf, wscanf, fwscanf, swscanf, vwscanf,
vfwscanf, vswscanf.
</para></listitem>

</itemizedlist>

</sect2>

<sect2 id="ov-new1.7-sec"><title>Security related changes</title>

<itemizedlist mark="bullet">

<listitem><para>
Getting a domain user's groups is hopefully more bulletproof now.
</para></listitem>

<listitem><para>
Cygwin now comes with a real LSA authentication package.  This must be
manually installed by a privileged user using the /bin/cyglsa-config
script.  The advantages and disadvantages are noted in
http://cygwin.com/ml/cygwin-developers/2006-11/msg00000.html
</para></listitem>

<listitem><para>
Cygwin now allows storage and use of user passwords in a hidden area of
the registry.  This is tried first when Cygwin is called by privileged
processes to switch the user context.  This allows, for instance, ssh
public key sessions with full network credentials to access shares on
other machines.
</para></listitem>

<listitem><para>
New options have been added to the mkpasswd and mkgroup tools to ease
use in multi-machine and multi-domain environments.  The existing
options have a slightly changed behaviour.
</para></listitem>

</itemizedlist>

</sect2>

<sect2 id="ov-new1.7-misc"><title>Miscellaneous</title>

<itemizedlist mark="bullet">

<listitem><para>
New ldd utility, similar to Linux.
</para></listitem>

<listitem><para>
New link libraries libdl.a, libresolv.a, librt.a.
</para></listitem>

<listitem><para>
Fallout from the long path names: If the current working directory is
longer than 260 bytes, or if the current working directory is a virtual
path (like /proc, /cygdrive, //server), don't call native Win32 programs
since they don't understand these paths.
</para></listitem>

<listitem><para>
On the first usage of a DOS path (C:\foo, \\foo\bar), the Cygwin DLL
emits a scary warning that DOS paths shouldn't be used.  This warning
may be disabled via the new CYGWIN=nodosfilewarning setting.
</para></listitem>

<listitem><para>
The CYGWIN environment variable option "server" has been removed.
Cygwin automatically uses cygserver if it's available.
</para></listitem>

<listitem><para>
Allow environment of arbitrary size instead of a maximum of 32K.
</para></listitem>

<listitem><para>
Don't force uppercase environment when started from a non-Cygwin
process.  Except for certain Windows and POSIX variables which are
always uppercased, preserve environment case.  Switch back to old
behaviour with the new CYGWIN=upcaseenv setting.
</para></listitem>

<listitem><para>
Detect and report a missing DLL on process startup.
</para></listitem>

<listitem><para>
Add /proc/registry32 and /proc/registry64 paths to access 32 bit and 64
bit registry on 64 bit systems.
</para></listitem>

<listitem><para>
Add the ability to distinguish registry keys and registry values with
the same name in the same registry subtree.  The key is called "foo" and
the value will be called "foo%val" in this case.
</para></listitem>

<listitem><para>
Align /proc/cpuinfo more closly to Linux content.
</para></listitem>

<listitem><para>
Add /proc/$PID/mounts entries and a symlink /proc/mounts pointing to
/proc/self/mounts as on Linux.
</para></listitem>

<listitem><para>
Optimized strstr and memmem implementation.
</para></listitem>

<listitem><para>
Remove backwards compatibility with old signal masks.  (Some *very* old
programs which use signal masks may no longer work correctly).
</para></listitem>

<listitem><para>
Cygwin now exports wrapper functions for libstdc++ operators new and
delete, to support the toolchain in implementing full C++ standards
conformance when working with shared libraries.
</para></listitem>

<listitem><para>
Different Cygwin installations in different paths can be run in parallel
without knowing of each other.  The path of the Cygwin DLL used in a
process is a key used when creating IPC objects.  So different Cygwin
DLLs are running in different namespaces.
</para></listitem>

<listitem><para>
Each Cygwin DLL stores its path and installation key in the registry.
This allows troubleshooting of problems which could be a result of
having multiple concurrent Cygwin installations.
</para></listitem>

</itemizedlist>

</sect2>

</sect1>