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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, assuming that the standard library functions  used
       are  thread  safe, such as memory allocation routines.  It provides in-
       memory compression and  decompression  functions,  including  integrity
       checks  of the uncompressed data.  This version of the library supports
       only one	compression method (deflation) but  other  algorithms  may  be
       added later with	the same stream	interface.

       Compression  can	 be  done  in  a  single step if the buffers are large
       enough or can be	done by	repeated calls of  the	compression  function.
       In the latter case, the application must	provide	more input and/or con-
       sume the	output (providing more output space) before each call.

       The library also	supports reading and writing files  in	gzip(1)	 (.gz)
       format 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 the 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	in  the	 files	test/example.c and test/minigzip.c, as well as
       other examples in the examples/ directory.

       Changes to this version are  documented	in  the	 file  ChangeLog  that
       accompanies the source.

       zlib is built in	to many	languages and operating	systems, including but
       not limited to Java, Python, .NET, PHP, Perl, Ruby, Swift, and Go.

       An experimental package to read and write files	in  the	 .zip  format,
       written on top of zlib by Gilles	Vollant	(, is	avail-
       able at:  and	 also  in  the
	      contrib/minizip  directory of the	main zlib source distribution.

       The zlib	web site can be	found at:

       The data	format used by the zlib	library	is described by	 RFC  (Request
       for Comments) 1950 to 1952 in the files:  (for	the  zlib  header  and
	      trailer format) (for the  deflate  compressed
	      data format)  (for	the  gzip  header  and
	      trailer format)

       Mark Nelson wrote an article about zlib for the Jan. 1997 issue of  Dr.
       Dobb's Journal; a copy of the article is	available at:

       Before  reporting  a  problem, please check the zlib web	site to	verify
       that you	have the latest	version	of zlib; otherwise, obtain the	latest
       version	and see	if the problem still exists.  Please read the zlib FAQ

       before  asking  for  help.    Send   questions	and/or	 comments   to,  or  (for	 the  Windows  DLL  version) to	Gilles Vollant

       Version 1.2.11

       Copyright (C) 1995-2017 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.

       Permission is granted to	anyone to use this software for	 any  purpose,
       including  commercial applications, and to alter	it and redistribute it
       freely, subject to the following	restrictions:

       1. The origin of	this software must not be misrepresented; you must not
	  claim	that you wrote the original software. If you use this software
	  in a product,	an acknowledgment in the product  documentation	 would
	  be appreciated but is	not required.

       2. Altered source versions must be plainly marked as such, and must not
	  be misrepresented as being the original software.

       3. This notice may not be removed or altered from any source  distribu-

       Jean-loup Gailly	       Mark Adler

       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

				  15 Jan 2017			       ZLIB(3)


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