| 1 |
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| 2 | Frequently Asked Questions about zlib
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| 3 |
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| 4 |
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| 5 | If your question is not there, please check the zlib home page
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| 6 | http://www.zlib.org which may have more recent information.
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| 7 | The lastest zlib FAQ is at http://www.gzip.org/zlib/zlib_faq.html
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| 8 |
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| 9 |
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| 10 | 1. Is zlib Y2K-compliant?
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| 11 |
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| 12 | Yes. zlib doesn't handle dates.
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| 13 |
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| 14 | 2. Where can I get a Windows DLL version?
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| 15 |
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| 16 | The zlib sources can be compiled without change to produce a DLL.
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| 17 | See the file win32/DLL_FAQ.txt in the zlib distribution.
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| 18 | Pointers to the precompiled DLL are found in the zlib web site at
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| 19 | http://www.zlib.org.
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| 20 |
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| 21 | 3. Where can I get a Visual Basic interface to zlib?
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| 22 |
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| 23 | See
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| 24 | * http://www.dogma.net/markn/articles/zlibtool/zlibtool.htm
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| 25 | * contrib/visual-basic.txt in the zlib distribution
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| 26 | * win32/DLL_FAQ.txt in the zlib distribution
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| 27 |
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| 28 | 4. compress() returns Z_BUF_ERROR.
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| 29 |
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| 30 | Make sure that before the call of compress, the length of the compressed
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| 31 | buffer is equal to the total size of the compressed buffer and not
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| 32 | zero. For Visual Basic, check that this parameter is passed by reference
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| 33 | ("as any"), not by value ("as long").
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| 34 |
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| 35 | 5. deflate() or inflate() returns Z_BUF_ERROR.
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| 36 |
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| 37 | Before making the call, make sure that avail_in and avail_out are not
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| 38 | zero. When setting the parameter flush equal to Z_FINISH, also make sure
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| 39 | that avail_out is big enough to allow processing all pending input.
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| 40 | Note that a Z_BUF_ERROR is not fatal--another call to deflate() or
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| 41 | inflate() can be made with more input or output space. A Z_BUF_ERROR
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| 42 | may in fact be unavoidable depending on how the functions are used, since
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| 43 | it is not possible to tell whether or not there is more output pending
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| 44 | when strm.avail_out returns with zero.
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| 45 |
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| 46 | 6. Where's the zlib documentation (man pages, etc.)?
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| 47 |
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| 48 | It's in zlib.h for the moment, and Francis S. Lin has converted it to a
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| 49 | web page zlib.html. Volunteers to transform this to Unix-style man pages,
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| 50 | please contact us ([email protected]). Examples of zlib usage are in the files
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| 51 | example.c and minigzip.c.
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| 52 |
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| 53 | 7. Why don't you use GNU autoconf or libtool or ...?
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| 54 |
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| 55 | Because we would like to keep zlib as a very small and simple
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| 56 | package. zlib is rather portable and doesn't need much configuration.
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| 57 |
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| 58 | 8. I found a bug in zlib.
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| 59 |
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| 60 | Most of the time, such problems are due to an incorrect usage of
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| 61 | zlib. Please try to reproduce the problem with a small program and send
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| 62 | the corresponding source to us at [email protected] . Do not send
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| 63 | multi-megabyte data files without prior agreement.
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| 64 |
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| 65 | 9. Why do I get "undefined reference to gzputc"?
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| 66 |
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| 67 | If "make test" produces something like
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| 68 |
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| 69 | example.o(.text+0x154): undefined reference to `gzputc'
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| 70 |
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| 71 | check that you don't have old files libz.* in /usr/lib, /usr/local/lib or
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| 72 | /usr/X11R6/lib. Remove any old versions, then do "make install".
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| 73 |
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| 74 | 10. I need a Delphi interface to zlib.
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| 75 |
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| 76 | See the contrib/delphi directory in the zlib distribution.
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| 77 |
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| 78 | 11. Can zlib handle .zip archives?
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| 79 |
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| 80 | Not by itself, no. See the directory contrib/minizip in the zlib
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| 81 | distribution.
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| 82 |
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| 83 | 12. Can zlib handle .Z files?
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| 84 |
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| 85 | No, sorry. You have to spawn an uncompress or gunzip subprocess, or adapt
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| 86 | the code of uncompress on your own.
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| 87 |
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| 88 | 13. How can I make a Unix shared library?
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| 89 |
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| 90 | make clean
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| 91 | ./configure -s
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| 92 | make
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| 93 |
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| 94 | 14. How do I install a shared zlib library on Unix?
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| 95 |
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| 96 | After the above, then:
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| 97 |
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| 98 | make install
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| 99 |
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| 100 | However, many flavors of Unix come with a shared zlib already installed.
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| 101 | Before going to the trouble of compiling a shared version of zlib and
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| 102 | trying to install it, you may want to check if it's already there! If you
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| 103 | can #include <zlib.h>, it's there. The -lz option will probably link to it.
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| 104 |
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| 105 | 15. I have a question about OttoPDF.
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| 106 |
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| 107 | We are not the authors of OttoPDF. The real author is on the OttoPDF web
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| 108 | site: Joel Hainley, [email protected].
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| 109 |
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| 110 | 16. Can zlib decode Flate data in an Adobe PDF file?
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| 111 |
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| 112 | Yes. See http://www.fastio.com/ (ClibPDF), or http://www.pdflib.com/ .
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| 113 | To modify PDF forms, see http://sourceforge.net/projects/acroformtool/ .
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| 114 |
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| 115 | 17. Why am I getting this "register_frame_info not found" error on Solaris?
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| 116 |
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