zlib 1.2.13 is a general purpose data compression library. All the code is thread safe. The data format used by the zlib library is described by RFCs (Request for Comments) 1950 to 1952 in the files https://tools.ietf.org/html/rfc1950 (zlib format), rfc1951 (deflate format) and rfc1952 (gzip format).

All functions of the compression library are documented in the file zlib.h (volunteer to write man pages welcome, contact [email protected]). A usage example of the library is given in the file test/example.c which also tests that the library is working correctly. Another example is given in the file test/minigzip.c. The compression library itself is composed of all source files in the root directory.

To compile all files and run the test program, follow the instructions given at the top of Makefile.in. In short ./configure; make test, and if that goes well, make install should work for most flavors of UNIX / Linux. For Windows, use one of the special makefiles in win32/ or contrib/vstudio/. For VMS, use make_vms.com.

Questions about zlib should be sent to <[email protected]>, or to Gilles Vollant <[email protected]> for the Windows DLL version.

The zlib's webpage is at: https://zlib.net
Before reporting a problem, please check this site to verify that you have the latest version of zlib; otherwise get the latest version and check whether the problem still exists or not.

You should read the zlib FAQ's at: https://zlib.net/zlib_faq.html before asking for help.

The changes made in version 1.2.13 are documented in the file ChangeLog.txt.

Unsupported third party contributions are provided in the contrib/ directory

zlib is available in Java using the java.util.zip package, documented at: https://java.sun.com/developer/technicalArticles/Programming/compression/

A Perl interface to zlib written by Paul Marquess [email protected] is available at CPAN (Comprehensive Perl Archive Network) sites, including: https://search.cpan.org/~pmqs/IO-Compress-Zlib/

A Python interface to zlib written by A.M. Kuchling [email protected] is available for Python 1.5+ and newer versions. Python documentation: https://docs.python.org/library/zlib.html

zlib is built-in into the TCL / TK languages as well: https://www.tcl.tk/man/tcl/TclCmd/zlib.html

An experimental package to read and write files in .zip format, written on top of zlib by Gilles Vollant [email protected], is available in the contrib/minizip directory of zlib

Notes for some targets:

• For Windows DLL versions, please see win32/DLL_FAQ.txt

• For 64-bit Irix deflate.c must be compiled without any optimization. With -O one libpng test fails. The test works in 32-bit mode (with the -n32 compiler flag) The compiler bug has been reported to SGI.

• zlib doesn't work with gcc v2.6.3 on a DEC 3000/300LX under OSF/1 2.1 It works when compiled with cc

• On Digital UNIX 4.0D (formely OSF/1) on AlphaServer, the cc option -std1 is necessary to get gzprintf working correctly. This is done by configure

• zlib doesn't work on HP-UX 9.05 with some versions of /bin/cc. It works with other compilers tho. Use make test to check your compiler.

• gzdopen is not supported on RISCOS or BEOS.

• For PalmOS, see: https://palmzlib.sourceforge.net