# How to build from source

## Requirements

### Common requirements

In order to build libssh, you need to install several components:

- A C compiler
- [CMake](http://www.cmake.org) >= 2.6.0.
- [openssl](http://www.openssl.org) >= 0.9.8
or
- [gcrypt](http://www.gnu.org/directory/Security/libgcrypt.html) >= 1.4

optional:
- [libz](http://www.zlib.net) >= 1.2

Note that these version numbers are version we know works correctly. If you
build and run libssh successfully with an older version, please let us know.

Windows binaries known to be working:

- http://www.slproweb.com/products/Win32OpenSSL.html
- http://www.winimage.com/zLibDll/index.html

We installed them in C:\Program Files

## Building
First, you need to configure the compilation, using CMake. Go inside the
`build` dir. Create it if it doesn't exist.

GNU/Linux, MacOS X, MSYS/MinGW:

    cmake -DCMAKE_INSTALL_PREFIX=/usr -DCMAKE_BUILD_TYPE=Debug ..
    make

On Windows you should choose a makefile gernerator with -G.

### CMake standard options
Here is a list of the most interesting options provided out of the box by
CMake.

- CMAKE_BUILD_TYPE:     The type of build (can be Debug Release MinSizeRel
                        RelWithDebInfo)
- CMAKE_INSTALL_PREFIX: The prefix to use when running make install (Default
                        to /usr/local on GNU/Linux and MacOS X)
- CMAKE_C_COMPILER:     The path to the C compiler
- CMAKE_CXX_COMPILER:   The path to the C++ compiler

### CMake options defined for libssh

Options are defined in the following files:

- DefineOptions.cmake

They can be changed with the -D option:

`cmake -DCMAKE_INSTALL_PREFIX=/usr -DCMAKE_BUILD_TYPE=Debug -DWITH_ZLIB=OFF ..`

### Browsing/editing CMake options

In addition to passing options on the command line, you can browse and edit
CMake options using `cmakesetup` (Windows), `cmake-gui` or `ccmake` (GNU/Linux
and MacOS X).

- Go to the build dir
- On Windows: run `cmakesetup`
- On GNU/Linux and MacOS X: run `ccmake ..`

### Useful Windows options:

If you have installed OpenSSL or ZLIB in non standard directories, maybe you
want to set:

OPENSSL_ROOT_DIR

and

ZLIB_ROOT_DIR

## Installing

If you want to install libssh after compilation run:

    make install

## Running

The libssh binary can be found in the `build/libssh` directory.
You can use `build/examples/samplessh` which is a sample client to
test libssh on UNIX.

## About this document

This document is written using [Markdown][] syntax, making it possible to
provide usable information in both plain text and HTML format. Whenever
modifying this document please use [Markdown][] syntax.

[markdown]: http://www.daringfireball.net/projects/markdown
