Updated: libpng-1.0.12-1

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

The libpng package has been updated to version 1.0.12-1.  libpng is a
library that provides routines to access and manipulate Portable
Network Graphics (PNG) images.  PNG is a lossless, patent-
unencumbered image format intended to replace GIF.

Since the png-developers group released version 1.0.12 and our
previous cygwin version was based on 1.0.11, I updated our package.
Also, since


- internal reorg to support scripted compilation
- split out the DLL into a separate package, in preparation for the
   new libpng-2.x package.
- uses auto-import so that -DPNG_STATIC and -DALL_STATIC are no
   longer needed.

Charles Wilson
libpng volunteer maintainer for cygwin


To update your installation, click on the "Install Cygwin now" link
on the http://cygwin.com/ web page.  This downloads setup.exe to your
system.  Then, run setup and update the libpng package -- and also
install the new libpng2 package.

Note that we have recently stopped downloads from sources.redhat.com
(aka cygwin.com) due to bandwidth limitations.  This means that you
will  need to find a mirror which has this update.

In the US,
is a reliable high bandwidth connection.

In the UK,
is usually up-to-date within 48 hours.

If one of the above doesn't have the latest version of this package
then you can either wait for the site to be updated or find another

If you have questions or comments, please send them to the Cygwin
mailing list at: cygwin@cygwin.com .  I would appreciate if you would
use this mailing list rather than emailing me directly.  This includes
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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
-DPNG_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
20010930, 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 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
The following have not (yet) and still need -DFOO_STATIC for
static builds:
   jpeg tiff bzip2 jbig gdbm

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