Errors while making tdlib example - cmake

Question

l am trying to build a java example for the td lib following the README(https://github.com/tdlib/td/tree/master/example/java)
I have got following mistackes. Please tell how can I fix it?
C:\Users\irina\td\jnibuild>cmake -DCMAKE_BUILD_TYPE=Debug -DTD_ENABLE_JNI=ON -DCMAKE_INSTALL_PREFIX:PATH=../example/java/td ..
-- Could NOT find ccache
-- Found OpenSSL: C:/OpenSSL-Win32/include optimized;C:/OpenSSL-Win32/lib/VC/ssleay32MD.lib;debug;C:/OpenSSL-Win32/lib/VC/ssleay32MDd.lib;optimized;C:/OpenSSL-Win32/lib/VC/libeay32MD.lib;debug;C:/OpenSSL-Win32/lib/VC/libeay32MDd.lib
-- Could NOT find ZLIB (missing: ZLIB_LIBRARY ZLIB_INCLUDE_DIR)
-- Could NOT find ZLIB (missing: ZLIB_LIBRARY ZLIB_INCLUDE_DIR)
CMake Warning at CMakeLists.txt:256 (message):
Not found zlib: skip TDLib, tdactor, tdnet, tddb
CMake Error: The following variables are used in this project, but they are set to NOTFOUND.
Please set them or make sure they are set and tested correctly in the CMake files:
ZLIB_LIBRARY
linked by target "tdutils" in directory C:/Users/irina/td/tdutils
-- Configuring incomplete, errors occurred!
See also "C:/Users/irina/td/jnibuild/CMakeFiles/CMakeOutput.log".
See also "C:/Users/irina/td/jnibuild/CMakeFiles/CMakeError.log".

Answer 1

ZLIB for Windows is a part of the GnuWin32 project (I'm not sure whether it is allowed to give links on SO). As I see, the CMakeLists.txt uses find_package to lookup the ZLIB library:
if (NOT ZLIB_FOUND)
find_package(ZLIB)
endif()
if (NOT ZLIB_FOUND)
message(WARNING "Not found zlib: skip TDLib, tdactor, tdnet, tddb")
return()
endif()
How the find_package command works is well described in the official documentation:
The command has two modes by which it searches for packages: “Module” mode and
“Config” mode. Module mode is available when the command is invoked with the
above reduced signature. CMake searches for a file called Find<package>.cmake
in the CMAKE_MODULE_PATH followed by the CMake installation. If the file is
found, it is read and processed by CMake. It is responsible for finding the
package, checking the version, and producing any needed messages. Many find-
modules provide limited or no support for versioning; check the module
documentation. If no module is found and the MODULE option is not given the
command proceeds to Config mode.
I've had a look into FindZLIB.cmake on my Windows machine. The module uses the following path: ZLIB_ROOT and the following registry keys:
"[HKEY_LOCAL_MACHINE\SOFTWARE\GnuWin32\Zlib;InstallPath]"
"$ENV{PROGRAMFILES}/zlib
So, as I understand, if you install GnuWin32 using the installer, the HKLM key will be written down into the registry and CMake will be able to find the path to ZLIB. If you wish to use just the zip-archive, the ZLIB_ROOT parameter must be correctly specified when you run CMake:
cmake -DZLIB_ROOT=<PATH-to-your-unpacked-zlib> -D.....