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 9. Why do I get "undefined reference to gzputc"?

    If "make test" produces something like

       example.o(.text+0x154): undefined reference to `gzputc'

    check that you don't have old files libz.* in /usr/lib, /usr/local/lib or
    /usr/X11R6/lib. Remove any old versions, then do "make install".

10. I need a Delphi interface to zlib.

    See the contrib/delphi directory in the zlib distribution.

11. Can zlib handle .zip archives?

    Not by itself, no.  See the directory contrib/minizip in the zlib
    distribution.

12. Can zlib handle .Z files?

    No, sorry.  You have to spawn an uncompress or gunzip subprocess, or adapt
    the code of uncompress on your own.

13. How can I make a Unix shared library?

    By default a shared (and a static) library is built for Unix.  So:

    make distclean
    ./configure
    make

14. How do I install a shared zlib library on Unix?

    After the above, then:

    make install

    However, many flavors of Unix come with a shared zlib already installed.
    Before going to the trouble of compiling a shared version of zlib and
    trying to install it, you may want to check if it's already there!  If you
    can #include <zlib.h>, it's there.  The -lz option will probably link to
    it.  You can check the version at the top of zlib.h or with the
    ZLIB_VERSION symbol defined in zlib.h .

15. I have a question about OttoPDF.

    We are not the authors of OttoPDF. The real author is on the OttoPDF web
    site: Joel Hainley, jhainley@myndkryme.com.

16. Can zlib decode Flate data in an Adobe PDF file?

    Yes. See http://www.pdflib.com/ . To modify PDF forms, see
    http://sourceforge.net/projects/acroformtool/ .

17. Why am I getting this "register_frame_info not found" error on Solaris?

    After installing zlib 1.1.4 on Solaris 2.6, running applications using zlib
    generates an error such as:

        ld.so.1: rpm: fatal: relocation error: file /usr/local/lib/libz.so:
        symbol __register_frame_info: referenced symbol not found

    The symbol __register_frame_info is not part of zlib, it is generated by
    the C compiler (cc or gcc).  You must recompile applications using zlib
    which have this problem.  This problem is specific to Solaris.  See
    http://www.sunfreeware.com for Solaris versions of zlib and applications
    using zlib.

18. Why does gzip give an error on a file I make with compress/deflate?

    The compress and deflate functions produce data in the zlib format, which
    is different and incompatible with the gzip format.  The gz* functions in
    zlib on the other hand use the gzip format.  Both the zlib and gzip formats
    use the same compressed data format internally, but have different headers
    and trailers around the compressed data.

19. Ok, so why are there two different formats?

    The gzip format was designed to retain the directory information about a
    single file, such as the name and last modification date.  The zlib format
    on the other hand was designed for in-memory and communication channel
    applications, and has a much more compact header and trailer and uses a
    faster integrity check than gzip.

20. Well that's nice, but how do I make a gzip file in memory?

    You can request that deflate write the gzip format instead of the zlib
    format using deflateInit2().  You can also request that inflate decode the
    gzip format using inflateInit2().  Read zlib.h for more details.

21. Is zlib thread-safe?

    Yes.  However any library routines that zlib uses and any application-
    provided memory allocation routines must also be thread-safe.  zlib's gz*
    functions use stdio library routines, and most of zlib's functions use the
    library memory allocation routines by default.  zlib's *Init* functions
    allow for the application to provide custom memory allocation routines.

    Of course, you should only operate on any given zlib or gzip stream from a
    single thread at a time.

22. Can I use zlib in my commercial application?

    Yes.  Please read the license in zlib.h.

23. Is zlib under the GNU license?

    No.  Please read the license in zlib.h.

24. The license says that altered source versions must be "plainly marked". So
    what exactly do I need to do to meet that requirement?

    You need to change the ZLIB_VERSION and ZLIB_VERNUM #defines in zlib.h.  In
    particular, the final version number needs to be changed to "f", and an
    identification string should be appended to ZLIB_VERSION.  Version numbers
    x.x.x.f are reserved for modifications to zlib by others than the zlib
    maintainers.  For example, if the version of the base zlib you are altering
    is "1.2.3.4", then in zlib.h you should change ZLIB_VERNUM to 0x123f, and
    ZLIB_VERSION to something like "1.2.3.f-zachary-mods-v3".  You can also
    update the version strings in deflate.c and inftrees.c.