# Installing librsync {#page_install}
## Requirements
To build librsync you will need:
* A C compiler and appropriate headers and libraries
* [CMake]
* Some build tool supported by CMake: [Make] is most common,
[Ninja] is nicer.
* [popt] command line parsing library
* [Doxygen] - optional, to build docs
[popt]: http://rpm5.org/files/popt/
[CMake]: http://cmake.org/
[Doxygen]: https://www.stack.nl/~dimitri/doxygen
[Ninja]: http://build-ninja.org
[Make]: https://www.gnu.org/software/make/
## Building
Generate the Makefile by running
$ cmake .
After building you can install `rdiff` and `librsync` for system-wide use.
$ make
To build and run the tests:
$ make check
To install:
$ sudo make install
To build the documentation:
$ make doc
librsync should be widely portable. Patches to fix portability bugs are
welcome.
If you are using GNU libc, you might like to use
MALLOC_CHECK_=2 ./rdiff
to detect some allocation bugs.
librsync has annotations for the SPLINT static checking tool.
## Build options
The build is customizable by using CMake options in the configure step:
$ cmake -D <option-name>=<value> .
If you are interested in building only the `librsync` target, you can skip
the `rdiff` build. In this way you don't need its dependencies (e.g. `popt`).
To do that, set the `BUILD_RDIFF` option to `OFF`:
$ cmake -D BUILD_RDIFF=OFF .
Be aware that many tests depend on `rdiff` executable, so when it is disabled,
also those tests are.
Compression support is under development (see
[#8](https://github.com/librsync/librsync/issues/8)). It is so disabled by
default. You can turn it on by using `ENABLE_COMPRESSION` option:
$ cmake -D ENABLE_COMPRESSION=ON .
To build code for debug trace messages:
$ cmake -D ENABLE_TRACE=ON .
## Ninja builds
CMake generates input files for an underlying build tool that will actually do
the build. Typically this is Make, but others are supported. In particular
[Ninja] is a nice alternative. To use it:
$ cmake -G Ninja .
$ ninja check
## Cygwin
With Cygwin you can build using gcc as under a normal unix system. It
is also possible to compile under Cygwin using MSVC++. You must have
environment variables needed by MSVC set using the Vcvars32.bat
script.