Frequently Asked Questions about zlib


If your question is not there, please check the zlib home page 
http://www.cdrom.com/pub/infozip/zlib/ which may have more recent information.


1) I need a Windows DLL
2) I need a Visual Basic interface to zlib
3) compress() returns Z_BUF_ERROR
4) deflate or inflate returns Z_BUF_ERROR
5) Where is the zlib documentation (man pages, etc...)?
6) Why don't you use GNU autoconf, libtool, etc...?
7) There is a bug in zlib.
8) I get "undefined reference to gzputc"



1) I need a Windows DLL

  The zlib sources can be compiled without change to produce a DLL.
  If you want a precompiled DLL, see http://www.winimage.com/zLibDll


2) I need a Visual Basic interface to zlib

  See http://www.tcfb.com/dowseware/cmp-z-it.zip
      http://web2.airmail.net/markn/articles/zlibtool/zlibtool.htm
  and contrib/visual-basic.txt

3) compress() returns Z_BUF_ERROR

  Make sure that before the call of compress, the length of the
  compressed buffer is equal to the total size of the compressed buffer
  and not zero.  For Visual Basic, check that this parameter is passed
  by reference ("as any"), not by value ("as long").


4) deflate or inflate returns Z_BUF_ERROR

  Make sure that before the call avail_in and avail_out are not zero.


5) Where is the zlib documentation (man pages, etc...)?

  It's in zlib.h for the moment. Volunteers to transform this
  to man pages, please contact jloup@gzip.org. Examples of zlib usage
  are in the files example.c and minigzip.c.


6) Why don't you use GNU autoconf, libtool, etc...?

  Because we would like to keep zlib as a very small and simple package.
  zlib is rather portable and doesn't need much configuration.


7) There is a bug in zlib.

  Most of the time, such problems are due to an incorrect usage
  of zlib. Please try to reproduce the problem with a small
  program and send us the corresponding source at zlib@quest.jpl.nasa.gov
  Do not send multi-megabyte data files without prior agreement.


8) I get "undefined reference to gzputc"

  If "make test" produces something like
     example.o(.text+0x174): 
  check that you don't have old files libz.* in /usr/lib, /usr/local/lib
  or /usr/X11R6/lib. Remove old versions then do "make install".