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.RE
.PP
VMS interprets standard Unix (or PC) return values as other, scarier-looking
things, so \fIunzip\fP instead maps them into VMS-style status codes.  The
current mapping is as follows:   1 (success) for normal exit, 0x7fff0001
for warning errors, and (0x7fff000? + 16*normal_unzip_exit_status) for all
other errors, where the `?' is 2 (error) for \fIunzip\fP values 2, 9-11 and
80-82, and 4 (fatal error) for the remaining ones (3-8, 50, 51).  In addition,
there is a compilation option to expand upon this behavior:  defining
RETURN_CODES results in a human-readable explanation of what the error
status means.
.PD
.\" =========================================================================
.SH BUGS
Multi-part archives are not yet supported, except in conjunction with
\fIzip\fP.  (All parts must be concatenated together in order, and then
``\fCzip \-F\fR'' (for \fIzip 2.x\fP) or ``\fCzip \-FF\fR'' (for
\fIzip 3.x\fP) must be performed on the concatenated archive in order to
``fix'' it.  Also, \fIzip 3.0\fP and later can combine multi-part (split)
archives into a combined single-file archive using ``\fCzip \-s\- inarchive
-O outarchive\fR''.  See the \fIzip 3\fP manual page for more information.)
This will definitely be corrected in the next major release.
.PP
Archives read from standard input are not yet supported, except with
\fIfunzip\fP (and then only the first member of the archive can be extracted).
.PP
Archives encrypted with 8-bit passwords (e.g., passwords with accented
European characters) may not be portable across systems and/or other
archivers.  See the discussion in \fBDECRYPTION\fP above.
.PP
\fIunzip\fP's \fB\-M\fP (``more'') option tries to take into account automatic
wrapping of long lines. However, the code may fail to detect the correct
wrapping locations. First, TAB characters (and similar control sequences) are
not taken into account, they are handled as ordinary printable characters.
Second, depending on the actual system / OS port, \fIunzip\fP may not detect
the true screen geometry but rather rely on "commonly used" default dimensions.
The correct handling of tabs would require the implementation of a query for
the actual tabulator setup on the output console.
.PP
Dates, times and permissions of stored directories are not restored except
under Unix. (On Windows NT and successors, timestamps are now restored.)
.PP
[MS-DOS] When extracting or testing files from an archive on a defective
floppy diskette, if the ``Fail'' option is chosen from DOS's ``Abort, Retry,
Fail?'' message, older versions of \fIunzip\fP may hang the system, requiring
a reboot.  This problem appears to be fixed, but control-C (or control-Break)
can still be used to terminate \fIunzip\fP.
.PP
Under DEC Ultrix, \fIunzip\fP would sometimes fail on long zipfiles (bad CRC,
not always reproducible).  This was apparently due either to a hardware bug
(cache memory) or an operating system bug (improper handling of page faults?).
Since Ultrix has been abandoned in favor of Digital Unix (OSF/1), this may not
be an issue anymore.
.PP
[Unix] Unix special files such as FIFO buffers (named pipes), block devices
and character devices are not restored even if they are somehow represented
in the zipfile, nor are hard-linked files relinked.  Basically the only file
types restored by \fIunzip\fP are regular files, directories and symbolic
(soft) links.
.PP
[OS/2] Extended attributes for existing directories are only updated if the
\fB\-o\fP (``overwrite all'') option is given.  This is a limitation of the
operating system; because directories only have a creation time associated
with them, \fIunzip\fP has no way to determine whether the stored attributes
are newer or older than those on disk.  In practice this may mean a two-pass
approach is required:  first unpack the archive normally (with or without
freshening/updating existing files), then overwrite just the directory entries
(e.g., ``\fCunzip -o foo */\fR'').
.PP
[VMS] When extracting to another directory, only the \fI[.foo]\fP syntax is
accepted for the \fB\-d\fP option; the simple Unix \fIfoo\fP syntax is
silently ignored (as is the less common VMS \fIfoo.dir\fP syntax).
.PP
[VMS] When the file being extracted already exists, \fIunzip\fP's query only
allows skipping, overwriting or renaming; there should additionally be a
choice for creating a new version of the file.  In fact, the ``overwrite''
choice does create a new version; the old version is not overwritten or
deleted.
.PD
.\" =========================================================================
.SH "SEE ALSO"
\fIfunzip\fP(1L), \fIzip\fP(1L), \fIzipcloak\fP(1L), \fIzipgrep\fP(1L),
\fIzipinfo\fP(1L), \fIzipnote\fP(1L), \fIzipsplit\fP(1L)
.PD
.\" =========================================================================
.SH URL
The Info-ZIP home page is currently at
.EX
\fChttp://www.info-zip.org/pub/infozip/\fR
.EE
or
.EX
\fCftp://ftp.info-zip.org/pub/infozip/\fR .
.EE
.PD
.\" =========================================================================
.SH AUTHORS
The primary Info-ZIP authors (current semi-active members of the Zip-Bugs
workgroup) are:  Ed Gordon (Zip, general maintenance, shared code, Zip64,
Win32, Unix, Unicode); Christian Spieler (UnZip maintenance coordination,
VMS, MS-DOS, Win32, shared code, general Zip and UnZip integration and
optimization); Onno van der Linden (Zip); Mike White (Win32, Windows GUI,
Windows DLLs); Kai Uwe Rommel (OS/2, Win32); Steven M. Schweda (VMS, Unix,
support of new features); Paul Kienitz (Amiga, Win32, Unicode); Chris
Herborth (BeOS, QNX, Atari); Jonathan Hudson (SMS/QDOS); Sergio Monesi
(Acorn RISC OS); Harald Denker (Atari, MVS); John Bush (Solaris, Amiga);
Hunter Goatley (VMS, Info-ZIP Site maintenance); Steve Salisbury (Win32);
Steve Miller (Windows CE GUI), Johnny Lee (MS-DOS, Win32, Zip64); and Dave
Smith (Tandem NSK).
.PP
The following people were former members of the Info-ZIP development group
and provided major contributions to key parts of the current code:
Greg ``Cave Newt'' Roelofs (UnZip, unshrink decompression);
Jean-loup Gailly (deflate compression);
Mark Adler (inflate decompression, fUnZip).
.PP
The author of the original unzip code upon which Info-ZIP's was based
is Samuel H. Smith; Carl Mascott did the first Unix port; and David P.
Kirschbaum organized and led Info-ZIP in its early days with Keith Petersen
hosting the original mailing list at WSMR-SimTel20.  The full list of
contributors to UnZip has grown quite large; please refer to the CONTRIBS