Setup Buildzlib VS15

Creating a zlib/libzip compression libaray for CNTK

We use the following installation paths in our instructions:

• libzip sources: c:\local\src\libzip-1.1.3
• zlib sources: c:\local\src\zlib\zlib-1.2.8
• Build directory for zlib and libzip binaries: c:\local\zlib-vs15

You can use any paths you like, but note the remark on target folder for binaries below.

• Install CMake. Include CMake binaries folder to your PATH
• Download libzip source code and unpack to c:\local\src\libzip-1.1.3
• Download zlib source code and unpack it to c:\local\src\zlib\zlib-1.2.8

There are two ways to build the lib/libzip compression libaray for CNTK, either through a batch file or manually.

Building through a batch file

In the directory Tools\devInstall\Windows you find the batch file buildZlibVS15.bat. This batch file takes three parameters to build the CNTK Protobuf library. The first parameter is the directory of the libzip source files you unpacked above, the second parameter is the directory of the zlib source files,the third parameter is the destination directory for the created library. In our case follow these steps from a standard Windows command prompt:

c:
cd \repos\cntk\Tools\devInstall\Windows
buildZlibVS15 c:\local\src\libzip-1.1.3 c:\local\src\zlib\zlib-1.2.8 c:\local\zlib-vs15

Set the environment variable ZLIB_PATH to the location of the created library (this is the third parameter in the command invocation above, not the sources location!

setx ZLIB_PATH c:\local\zlib-vs15

Manual build steps for a CNTK compression library

IMPORTANT! The following aspects are important:

• Build commands for zlib and libzip should use the same target folder for binaries (specified via -DCMAKE_INSTALL_PREFIX parameter in cmake command below)
• Build order is important. You should build zlib first because libzip is dependent on it

Command prompt environment for build

Launch a 64-bit Visual Studio 2015 development environment. The most convenient way is to execute the batch file vcvarsall.bat in the Visual Studio directory with the required paramaters from a standard windows command shell:

    "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" amd64

If you can't find this batchfile on your system, please revisit the installation of VS2015, and make sure you have the 'Common Tools for Visual C++ 2015' option selected.

Building zlib

Execute the following commands from VS2015 x64 Native Tools Command Prompt:

cd c:\local\src\zlib\zlib-1.2.8
mkdir build
cd build
cmake .. -G"Visual Studio 14 2015 Win64" -DCMAKE_INSTALL_PREFIX="c:\local\zlib-vs15"
msbuild /P:Configuration=Release INSTALL.vcxproj

Building libzib

Execute the following commands from VS2015 x64 Native Tools Command Prompt:

cd c:\local\src\libzip-1.1.3
mkdir build
cd build
cmake .. -G"Visual Studio 14 2015 Win64" -DCMAKE_INSTALL_PREFIX="c:\local\zlib-vs15"
msbuild libzip.sln /t:zip /P:Configuration=Release
cmake -DBUILD_TYPE=Release -P cmake_install.cmake

MSBuild command above may generate some warnings. It is expected and may be ignored.

The last cmake command from the list above will generate the following error:

CMake Error at src/cmake_install.cmake:34 (file):
  file INSTALL cannot find "C:/libzip/build/src/Release/zipcmp.exe".

It is expected and may be ignored - all required binaries (zip.dll and zlib.dll) should be already in c:\local\zlib-vs15

Preparing the environment

• Set the following environment variable:

setx ZLIB_PATH c:\local\zlib-vs15