Boost C++ Libraries of the most highly regarded and expertly designed C++ library projects in the world. Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

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Build and install

Usage as a single header file

Outcome v2 comes in single header file form. This is regenerated per commit. To fetch on Linux:




If you have curl installed:

curl -O -J -L

Otherwise, simply download the raw file from above and place it wherever it suits you. If you might be debugging using Microsoft Visual Studio, you may find the debugger visualisation file at useful to include into your build.

Usage from the vcpkg package manager

This is particularly easy, and works on Mac OS, Linux and Microsoft Windows:

vcpkg install outcome

Outcome appears at <boost/outcome/outcome.hpp>. This is a full copy of Outcome, so Experimental Outcome and all the usual headers are where you would expect.

Usage from the Conan package manager

(thanks to Théo Delrieu for contributing this support)

At the command line, add the bintray repo for Outcome to conan:

conan remote add outcome

Now simply add this to your Conan build:


Outcome will be made available by Conan at <outcome.hpp>.

Usage from the cmake hunter package manager

Outcome has not been submitted to the main cmake hunter package manager repo yet. You can however add it as a git submodule:

cd yourthirdpartyrepodir
git submodule add
git submodule add
cd ..
git submodule update --init --recursive

Now tell cmake hunter about a git submoduled cmake hunter package by adding to your project’s cmake/Hunter/config.cmake:

hunter_config(quickcpplib GIT_SUBMODULE "yourthirdpartyrepodir/quickcpplib")
hunter_config(outcome GIT_SUBMODULE "yourthirdpartyrepodir/outcome")

… and finally to your CMakeLists.txt, now add outcome as if it were an ordinary cmake hunter package:

find_package(quickcpplib CONFIG REQUIRED)
find_package(outcome CONFIG REQUIRED)

Now you tell cmake to link to outcome as usual (see below for cmake targets):

target_link_libraries(mytarget outcome::hl)

Usage as a git submodule

If you are very keen on tracking very latest Outcome, you can add it as a git submodule to your project so you can keep abreast of bug fixes. Here is how:

git submodule add
cd outcome
git checkout master
git submodule update --init --recursive

After this you can bring Outcome into your code using:

#include "outcome/single-header/outcome.hpp"

That’s it, you are ready to go. From time to time, you may wish to update to latest:

cd outcome
git pull
git submodule update

Usage as a stable source tarball

If you would prefer a single source tarball of the stable and develop branches known to have had all unit tests passing on all platforms, containing all the documentation, tests and sources, this can always be retrieved from:

This tarball is automatically generated when Outcome fully compiles and passes all unit tests on all platforms tested by the CIs. This currently includes:

All unit tests are executed under the Address and Undefined Behaviour sanitisers.

It should be emphasised that newer compilers are not tested, so there is an unlikely chance that the tarball may not work on a newer compiler.

Running the unit test suite

To run the unit test suite you will need cmake 3.3 or later installed.

mkdir build
cd build
cmake ..
cmake --build .

On some cmake generators (Visual Studio, Xcode) you may need to tell cmake build a configuration like Release or Debug. Similarly, ctest needs to be told the same e.g.

mkdir build
cd build
cmake ..
cmake --build . --config Release
ctest -C Release

Per commit, tests are run by Travis and uploaded to a CDash dashboard here.

CMake find_package() imported targets support

Outcome fully complies with cmake install, so by installing Outcome, it can be found by cmake’s find_package().

mkdir build
cd build
cmake ..
cmake --build .
sudo cmake --build . --target install

Modular CMake build support

If you are using Outcome in a CMake project, Outcome is a “modular cmake” project using only modern cmake 3 throughout. This lets you add the Outcome directory as a cmake subdirectory with no unexpected consequence on the rest of your cmake. You will need to be using cmake 3.3 or better.

  "${CMAKE_CURRENT_SOURCE_DIR}/outcome"  # path to outcome source
  "${CMAKE_CURRENT_BINARY_DIR}/outcome"  # your choice of where to put binaries
  EXCLUDE_FROM_ALL                       # please only lazy build outcome on demand

Outcome’s cmake has the following useful products:

Last revised: April 02, 2021 at 11:06:20 +0100

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