Requirements
Install with CMake
Install with vcpkg
Usage with CMake
Using FetchContent
CMake project options
Building the API docs

You will need a C++20 compiler and CMake to build and use the library.
There are no additional required dependencies, but Catch2 is needed to build the tests.

The full list of requirements are:

• C++20 compiler (gcc 11, clang 15, msvc 14.30 or later)
• CMake 3.21 or later
• Catch2 3.3 or later (optional, only needed for the tests)

The library works on Windows, Linux, and macOS. The tested compilers for each of these platforms are:

• gcc and clang on Linux
• msvc and clang-cl on Windows
• gcc and clang (not AppleClang) on macOS

As the only real requirement for using the library is a compiler with C++20 support, and the library doesn't include any platform or compiler specific code, other platforms and compilers would probably also work, but only the ones listed above are tested.

The library uses CMake as its build system, which can also be used to install it:

# Clone the repository
git clone https://github.com/KRM7/gapp.git --branch v1.0.0
# Go to the library's build directory
cd gapp/build
# Configure cmake with the relevant options
cmake .. -DCMAKE_BUILD_TYPE=Release -DBUILD_TESTING=OFF
# Build the library
cmake --build . --config Release
# Install the library
sudo cmake --install . --config Release

Alternatively, there is a utility script provided that can be used to install the library in fewer steps:

git clone https://github.com/KRM7/gapp.git --branch v1.0.0
sudo bash gapp/tools/install.sh

The script will perform the installation steps detailed above for all 3 configurations of the library. If you want to configure CMake differently from the default, you can pass arguments to the install script as you would do to CMake, for example:

sudo bash gapp/tools/install.sh -DBUILD_TESTING=ON

If you don't have elevated privileges, you will need to specify a location for the installation using CMAKE_INSTALL_PREFIX during the configuration step:

cmake .. -DCMAKE_BUILD_TYPE=Release -DBUILD_TESTING=OFF -DCMAKE_INSTALL_PREFIX=/some/install/path

If you do this, you will also need to specify this path later on when using find_package:

find_package(gapp REQUIRED PATH /some/install/path)

There are 3 configurations supported by the library: Debug, Release, and RelWithDebInfo. If you don't specify the build type during the above installation steps, the RelWithDebInfo config will be used as the default. If you want to install the library for more than 1 configuration, you will need to repeat the above steps for all of the configurations you want.

If Catch2 is installed, you can build and run the tests of the project as:

# In the build directory
cmake .. -DBUILD_TESTING=ON
cmake --build .
ctest --output-on-failure --schedule-random

The library can also be installed using Microsoft's vcpkg package manager:

vcpkg install gapp

Once the library is installed, you can link against it using the namespaced CMake target exported by the project. The name of this target is gapp::gapp. A minimal CMakeLists.txt file of a project that depends on the library could for example look like:

project("example_project")

# Find the installed library
find_package(gapp CONFIG REQUIRED)

add_executable(example_project "example.cpp")
# Link the library to the executable
target_link_libraries(example_project PRIVATE gapp::gapp)

and the actual C++ code that uses the library could be:

// example.cpp
#include <gapp/gapp.hpp> // include everything from the library

int main() {
    return gapp::rng::randomBool();
}

The library can also be used as a subdirectory, allowing you to use CMake's FetchContent instead of manually downloading and installing the library:

project("example_project")

Include(FetchContent)

FetchContent_Declare(
    gapp
    GIT_REPOSITORY https://github.com/KRM7/gapp.git
    GIT_TAG        v1.0.0
)
FetchContent_MakeAvailable(gapp)

add_executable(example_project "example.cpp")
target_link_libraries(example_project PRIVATE gapp::gapp)

Note that if you use FetchContent instead of installing the library, the include paths of the library's headers will be slightly different, ie. you will need to do #include <gapp.hpp> instead of the usual #include <gapp/gapp.hpp>.

• GAPP_DETERMINISM - When this option is ON, additional interface compiler flags will be added to the library target which are required for reproducible runtime results across debug and release builds. This only includes compiler flags which are not typically on by default, and does not prevent the use of other compiler flags which might cause non-reproducible results, such as the fast-math flags. It is recommended to avoid the use of these flags when this option is ON. The default value is ON.

• BUILD_SHARED_LIBS - When this option is ON, the library will be built as a shared library instead of a static one. Note that you have to choose between the static and shared versions of the library when installing it, you can't install both. The default value is OFF.

• BUILD_TESTING - When this option and the GAPP_BUILD_TESTS options are both ON, the tests will also be built along with the library. The default value is ON.

• GAPP_BUILD_TESTS - When this option and the BUILD_TESTING options are both ON, the tests will also be built along with the library. This option can be used to control when the tests are built when using the library as a subproject, without having to change the value of BUILD_TESTING. The default value is ON.

• GAPP_BUILD_BENCHMARKS - When this options and the BUILD_TESTING options are both ON, the benchmarks will also be built. The default value is OFF.

• GAPP_BUILD_EXAMPLES - When this option is ON, the usage examples in the examples folder will also be built. The default value is OFF.

• GAPP_USE_WERROR - When this option is ON, all warnings will be treated as errors during the build. The default value is ON.

• GAPP_USE_LTO - When this option is ON, the library will be built using link-time optimizations in the optimized configurations (Release and RelWithDebInfo). This option has no effect on Debug builds. The default value is OFF.

• GAPP_USE_MARCH_NATIVE - When this option is ON, the library will be optimized specifically for the host architecture in the optimized configurations (Release and RelWithDebInfo). This has no effect on Debug builds. The default value is OFF.

• GAPP_DISABLE_ASSERTS - When this option is ON, all assertions in the library will be disabled, even when NDEBUG is not defined. Defining NDEBUG disables assertions in the library regardless the value of this option. The default value is OFF.

• GAPP_DISABLE_EXCEPTIONS - When this option is ON, the library will be built with exception support disabled. The default value is OFF.

• GAPP_DISABLE_RTTI - When this option is ON, the library will be built without run-time type information. The default value is OFF.

The options are specified during the configuration step of CMake, for example:

# From the build directory
cmake .. -DGAPP_DISABLE_EXCEPTIONS=ON -DGAPP_DISABLE_RTTI=ON
cmake --build .

If you want to specify additional compiler flags when building the library, you should do it through the GAPP_CXX_FLAGS variable. The value of the CMAKE_CXX_FLAGS variable will be ignored by the project. All of the flags specified through GAPP_CXX_FLAGS are in addition to the default flags, they will not overwrite them.

The API documentation can be generated by running the docs/api/generate_api_docs.sh script. The output will be in the docs/api/sphinx-out directory.