The easiest and quickest way is to install pre-built binaries available at many package repositories. The caveat: some repositories are slow to update and often include a very old version of Unison.
Alternatively, some pre-built binaries are made available at https://github.com/bcpierce00/unison/releases for macOS, Linux and Windows. No specific installation is needed, just unpack the files at a location of your choosing.
Many packaging systems, including source-based systems like pkgsrc
and binary repositories like Debian GNU/Linux, make it easy to build
from source by handling all the dependencies for you and encoding the
unison build recipe. Please refer to instructions provided by the
packaging system. (Issues about packaging systems should be filed
with those systems, and not in the unison issue tracker.)
- A C99 compiler (e.g. gcc, clang)
- A recent version of OCaml compiler (version 4.08 at minimum) -- see https://ocaml.org/. (Note that ocaml upstream says that 5.x is experimental. The standard approach is the most recent 4.x ocaml release.)
- make (any of GNU, BSD, Solaris variants works)
- Basic POSIX tools (e.g., echo, install, rm, sh, sed, touch)
- lablgtk3 and its prerequisites (GTK 3 and its dependencies)
- ocamlfind (there is backup code to operate without it in some circumstances)
- pkg-config
- libinotify
- sed
- LaTeX
- pdf2ps (optional, for PS output; included with Ghostscript, for example)
- HEVEA (https://hevea.inria.fr/) (optional, for HTML and text formats)
- Lynx (optional, for text format)
- (for developers only) HEVEA and Lynx are required to re-build the manual included in the Unison binary
To build from source, first ensure that all prerequisites are installed. See each prerequisite's documentation for instructions, or use a package manager.
Building from source is as simple as changing to the source directory and executing:
make
If you are using OPAM then opam exec -- make
may work for you, as opam needs
to set up a specific environment.
Presence of lablgtk3 is detected automatically to build the GUI. On BSDs, the presence of libinotify is detected automatically. On systems supported by one of the unison-fsmonitor variants, it is built automatically.
If you want to build only the GUI, type make gui
. You can type make tui
if you have lablgtk3 installed but don't want the GUI built. Type
make fsmonitor
to build only the filesystem monitor.
To install:
- set
$PREFIX
in the environment if you don't want /usr/local - optionally set
$DESTDIR
- run
make install
.
The set of installed files (paths from the source directory) should be
src/unison (the main executable for TUI/CLI)
src/unison-gui (the main executable for GUI)
src/unison-fsmonitor (optional, on some build platforms)
man/unison.1 (optional, manual page)
doc/unison-manual.* (optional, user manual in different formats)
To cross-compile for a different target, you need to have a cross-compilation
toolchain including both a cross-compiling C compiler and a cross-compiling
OCaml compiler. When you have cross-compilation toolchain in place, building
Unison from source works according to instructions above. You just have to add
a TOOL_PREFIX
argument to make
to indicate which toolchain to use (and
ensure the tools are in $PATH
).
For example, to build a native Windows 64-bit executable using the MinGW cross-compilation toolchain:
make TOOL_PREFIX=x86_64-w64-mingw32-
Building the manual page and documentation does not work when cross-compiling. To build the documentation, first build Unison without cross-compilation.
First, note that macOS is a mostly-POSIX system and see that section above.
Second, note that macOS by default is missing a number of expected tools, including POSIX-required system headers (e.g. all of /usr/include). The standard approach on macOS is to install either Command Line Tools or Xcode, so that one has a working C99/mostly-POSIX environment. These also allow building against the libraries required for the mac-native GUI.
There is no support in the unison sources for unison-fsmonitor on macOS. See https://github.com/bcpierce00/unison/wiki/Software-for-use-with-Unison for a list of fsmonitor implementations maintained outside the unison source tree.
The mostly-POSIX instructions above will build the text user interface, the GTK GUI and, if you have native GUI headers/libs, also the macOS native GUI.
To build only the macOS native GUI, execute:
make macui
The built application will be located at src/uimac/build/Default/Unison.app
.
Builds are possible with MS Visual C++ (MSVC) and MinGW-w64 compilers.
To build Unison for usage within Cygwin environment (not a native Windows executable), follow build instructions for Unix-like OS above.
The build system automatically detects if the build is of MSVC, MinGW or Cygwin
GNU C (not native Windows) type based on the first OCaml compiler (ocamlc and
ocamlopt) found on PATH. Thus, if you have multiple compilers, you can easily
select between these methods by adjusting the PATH accordingly when running
make
.
Building with MinGW, you need a Cygwin installation as the POSIX-like build environment (if you are using OPAM, this can be installed automatically by OPAM). Cygwin is not required to run the produced executables. You need to have the following prerequisites:
- MinGW gcc and MinGW binutils (Cygwin package example mingw64-x86_64-gcc-core)
- A recent version of OCaml compiler (version 4.08 at minimum) which itself is built with MinGW gcc (it is possible to find pre-compiled binaries); do not use the Cygwin OCaml package as that is not compiled with MinGW. If using OPAM, be sure to include the system-mingw OPAM package when installing the OCaml compiler.
- GNU make
- A POSIX shell (available in Cygwin by default)
To build, change to directory where Unison source code is and execute:
make
If all goes well, the following files will be produced:
src/unison.exe (the main executable for TUI/CLI)
src/unison-gui.exe (the main executable for GUI, optional, see below)
src/unison-fsmonitor.exe (filesystem monitor, optional)
You can check which DLLs are needed by the built binary by executing
cygcheck src/unison.exe
or ldd src/unison.exe
.
For building the GUI (optional), you also need the following:
- MinGW GTK 3 and its dependencies (Cygwin package example mingw64-x86_64-gtk3)
- Some MinGW GTK icon theme (optional, but recommended; Cygwin package example mingw64-x86_64-adwaita-icon-theme)
- lablgtk3 and its prerequisites (ocamlfind, dune build system)
Building lablgtk3 from source is complicated. It is recommended to use OPAM for that (Cygwin package name opam). Make sure that OPAM uses the MinGW version of gcc and binutils.
When building with MSVC, a Cygwin installation is not needed. It is possible to find pre-compiled OCaml compiler binaries, but it may be easiest to use OPAM as it will also automatically set up the correct environment for using MSVC and NMAKE. You need to have the following prerequisites:
- Microsoft Visual C++ (MSVC). A complete Visual Studio installation is not required, having Build Tools installed is sufficient. The build tools, including NMAKE, must be found in PATH.
- A recent version of OCaml compiler (version 4.08 at minimum) which itself is built with MSVC. If using OPAM, be sure to include the system-msvc OPAM package when installing the OCaml compiler.
To build, change to directory where Unison source code is and execute:
nmake
If all goes well, the following files will be produced:
src\unison.exe (the main executable for TUI/CLI)
src\unison-gui.exe (the main executable for GUI, optional, see below)
src\unison-fsmonitor.exe (filesystem monitor, optional)
For building the GUI (optional) with MSVC, you also need the following:
- A native Windows GTK 3 installation (try https://github.com/wingtk/gvsbuild). Do not use GTK for Cygwin or MinGW. Make sure the installation location (typically C:\gtk\bin) is in the PATH environment variable. If building lablgtk3/cairo2 fails with errors related to pkgconf or pkg-config then you may also need to set the PKG_CONFIG_PATH environment to point to C:\gtk\lib\pkgconfig (adjust according to your GTK installation location).
- lablgtk3 and its prerequisites (ocamlfind, dune build system)
Once built, a GTK 3 installation must be found in PATH or DLLs for GTK 3 be present where unison-gui.exe is located in order to run the GUI.
There are some additional options that control the build process:
- NATIVE: If you can't compile a native binary for your platform then add
NATIVE=false
as argument tomake
. This will produce a single native executable with OCaml runtime and Unison bytecode embedded. - CFLAGS, CPPFLAGS, LDFLAGS, LDLIBS control the build process as usual. OCaml compiler will pass these arguments on to the C compiler and linker.
- To produce a statically linked executable, add arguments suitable for your
platform and toolchain in your LDFLAGS. Static linking mostly makes no
difference because some widely-used C libraries, like glibc, do not allow
static linking, GTK does not allow static linking and there is nothing to
link statically for the textual user interface in Windows and Cygwin.
Examples of LDFLAGS values to enable static linking:
-static
or-Wl,-static
for gcc (should also work for clang);-link -static
for gcc in Windows (MinGW, Cygwin, MSYS2) ("-link" is required due to flexlink being used in the toolchain).