# Build instructions for libssh

The OVITO package includes a binary version of the libssh library licensed under the GNU Lesser General Public License (LGPLv2.1). In accordance with the requirements of this license, this page provides instructions on how to rebuild a compatible version of the library from source code.

## Windows

OVITO for Windows includes binaries that have been built from the unmodified sources of libssh 0.10.5. The following commands have been used to generate them:

    # Compiler: Microsoft Visual C++ 2019 (command line tools)
    # OpenSSL version: 1.1.1u
    # zlib version: 1.2.13
    cd libssh-0.10.5
    mkdir build
    cd build
    cmake -G "NMake Makefiles" ^
      -DCMAKE_BUILD_TYPE=Release ^
      -DCMAKE_INSTALL_PREFIX=../../libssh ^
      -DZLIB_INCLUDE_DIR=%cd:\=/%/../../zlib/include ^
      -DZLIB_LIBRARY=%cd:\=/%/../../zlib/lib/zlib.lib ^
      -DWITH_SERVER=OFF ^
      -DWITH_GSSAPI=OFF ^
      -DWITH_EXAMPLES=OFF ^
      -DOPENSSL_ROOT_DIR=%cd:\=/%/../../openssl ^
      ..
    nmake install

## Linux

OVITO for Linux includes a shared library that has been built from the unmodified sources of libssh 0.10.5. The following commands were used to build it:

    # Build platform: CentOS 7
    # Compiler: GCC 10
    cmake -G Ninja -DCMAKE_BUILD_TYPE=Release -DWITH_SERVER=OFF .
    cmake --build . --parallel
    cmake --install .

## macOS

OVITO for amcOS includes a shared library that has been built from the unmodified sources of libssh 0.10.5. The following commands were used to build it:

    export OPENSSL_ROOT_DIR=...
    cmake -G Ninja \
        -DCMAKE_BUILD_TYPE=Release \
        -DWITH_SERVER=OFF \
        -DWITH_EXAMPLES=OFF \
        -DWITH_PKCS11_URI=ON \
        -DCMAKE_OSX_DEPLOYMENT_TARGET=10.15 \
        ..
    cmake --build . --parallel && cmake --install .