ZLIB(3)                                                                ZLIB(3)

       zlib - compression/decompression library

       [see zlib.h for full description]

       The  zlib  library  is a general purpose data compression library.  The
       code is thread safe.  It provides in-memory compression and  decompres-
       sion  functions,  including  integrity checks of the uncompressed data.
       This version of  the  library  supports  only  one  compression  method
       (deflation)  but other algorithms will be added later and will have the
       same stream interface.

       Compression can be done in a single  step  if  the  buffers  are  large
       enough  (for  example  if  an input file is mmap'ed), or can be done by
       repeated calls of the compression function.  In the  latter  case,  the
       application  must provide more input and/or consume the output (provid-
       ing more output space) before each call.

       The library also supports reading and writing files in gzip (.gz)  for-
       mat with an interface similar to that of stdio.

       The library does not install any signal handler. The decoder checks the
       consistency of the compressed data, so the library should  never  crash
       even in case of corrupted input.

       All  functions  of  the  compression library are documented in the file
       zlib.h.  The distribution  source  includes  examples  of  use  of  the
       library the files example.c and minigzip.c.

       A  Java implementation of zlib is available in the Java Development Kit


       A   Perl   interface   to   zlib,   written  by  Paul  Marquess  (pmar- is available at CPAN (Comprehensive Perl  Archive
       Network) sites, such as:


       A Python interface to zlib written by A.M. Kuchling <> is
       available from the Python Software Association sites, such as:


       Questions about zlib should be sent to:

       or,  if  this  fails,  to  the  author
              addresses given below.  The zlib home page is:


       The data format used by the zlib library is described by  RFC  (Request
       for Comments) 1950 to 1952 in the files:

     (zlib format)
              rfc1951.txt (deflate format)
              rfc1952.txt (gzip format)

       These documents are also available in other formats from:


       Version 1.1.4 Copyright (C) 1995-2002 Jean-loup Gailly (
       and Mark Adler (

       This software is provided "as-is," without any express or implied  war-
       ranty.   In  no  event  will the authors be held liable for any damages
       arising from the use of this software.  See the distribution  directory
       with  respect  to  requirements  governing redistribution.  The deflate
       format used by zlib was defined by Phil Katz.   The  deflate  and  zlib
       specifications  were  written  by  L. Peter Deutsch.  Thanks to all the
       people who reported problems  and  suggested  various  improvements  in
       zlib; who are too numerous to cite here.

       UNIX manual page by R. P. C. Rodgers, U.S. National Library of Medicine

                                 11 March 2002                         ZLIB(3)