Updated: jpeg-6b-7

Charles Wilson cwilson@ece.gatech.edu
Tue Dec 31 07:35:00 GMT 2002

The jpeg package has been updated to version 6b-7.  When I released
6b-6, I forgot to include a few small corrections that folks had
pointed out to me over the eight months since 6b-4 had been released.

CHANGES (relative to jpeg-6b-4):

   1. Internal changes to facilitate easier building/maintainance
   2. jpeg is now built using the 'auto-import' features of
      recent binutils.
   3. Add C++ guards to jpeglib.h
   4. fix some text/binary issues with the utilities when
      using stdin/stdout.

Charles Wilson


To update your installation, click on the "Install Cygwin now" link on
the http://www.cygwin.com/ web page.  This downloads setup.exe
to your system.

Run setup and answer all of the questions.  Note that you can
no longer download directly from sources.redhat.com; use a
mirror.  The mirrors below have the latest version of this

ftp://mirrors.rcn.net/pub/sourceware/cygwin/ (US)
ftp://linux.sarang.net/mirror/development/compiler/cygwin/ (Korea)
ftp://ftp.mirror.ac.uk/sites/sourceware.cygnus.com/pub/cygwin (UK)

The setup.exe program will figure out what needs to be updated on your
system and should install the jpeg package automatically.

If you have questions or comments, please send them to the Cygwin
mailing list at:  cygwin@sources.redhat.com .  I would appreciate if you
would use this mailing list rather than emailing me directly. This
includes ideas and comments about the setup utility or Cygwin general.

If you want to make a point or ask a question the Cygwin mailing list is
the appropriate place.


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o Now uses the auto-import functionality of newer binutils, and
doesn't use __declspec(dllimport).  This means you no longer need
-DJPEG_STATIC or -DALL_STATIC when compiling objects intended for
static linking. Just compile as normal. HOWEVER, you need to use
a special flags when linking statically: 'gcc -static'. For dynamic
linking, you need no special link-time flags (assuming you're using
binutils newer than 20011002, when --enable-auto-import was made
the default).

   -- PRO: no compile time flags needed when building
           client programs; ONLY need a link-time flag
           linking to static libraries.  NO special flags
           at compile-time nor link-time when linking to
           dynamic links.
   -- CON: (partial): if using binutils older than 20010930,
           you now need a special linktime flag for dynamic
           linking (-Wl,--enable-auto-import).  However,
           with an up-to-date binutils, you don't need this.

o The semi-official 'lossless jpeg' patch is included in this build, and
is distributed as part of the source archive (see below). The lossless
jpeg patch is NOT related to the "new" JPEG2000 specification.
JPEG2000 is NOT supported by this package.

o Includes several utilities for manipulating jpeg files. The binary
package includes dynamically linked versions of these utilities,
although the build process will make both dynamically and statically
linked versions.

o Building the package from source requires gcc-2.95.3-5 and
binutils-20011002-1 or later

o If you are building a package that depends on libjpeg, and you wish to
link *statically*, just use 'gcc -static' when linking your package.
There no need to -Ddefine anything special when compiling your object

o No special -Ddefine options or link options are needed when building a
package that depends on libjpeg and you want to link dynamically

o The following packages have been converted from old style
"-DFOO_STATIC" to the new autoimport style of DLL structure:
     ncurses   readline   gettext   zlib
     libpng    xpm-nox    jpeg      jbig
The following have not (yet) been converted, and still need
-DFOO_STATIC for static builds:
     tiff      bzip2      gdbm

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