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Fetching the library with CMake FetchContent()

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While header-only libraries can be trivially included without any use of the build system, some users might prefer to manage their dependencies in a unified manner through CMake. For this purpose UTL provides two INTERFACE targets:

UTL::include
UTL::single_include

corresponding to include/ and single_include/ directories.

FetchContent() example

CMake FetchContent() can be used to automatically download and expose UTL as a library:

# Fetch library from GitHub
include(FetchContent)

FetchContent_Declare(
    UTL
    GIT_REPOSITORY https://github.com/DmitriBogdanov/UTL.git
    GIT_TAG        v8.3.3
)

FetchContent_MakeAvailable(UTL)

Note: While GIT_TAG argument can be omitted to download the latest commit automatically, it is not recommended due to possible breaking changes in the newer versions of the library.

CPM example

The same thing can be done using CPM for dependency management:

# Fetch library from GitHub
include(cmake/CPM.cmake)

CPMAddPackage("gh:DmitriBogdanov/UTL#v8.3.3")

Note: Use commit SHA instead of the tag to download specific commits.

Linking the library

Fetched library can now be linked to a target:

# Link library to the executable
add_executable(main_target main.cpp)

target_link_libraries(main_target UTL::include)

Which allows us to use it in main.cpp:

#include "UTL/json.hpp"

int main() {
    // <code using utl::json>
}

Questions and answers

Q: Does this library set any CMake options or variables?

A: The library operates exclusively on targets, no global variables are ever set.

Q: What if I'm using an older commit that doesn't correspond to the current documentation?

A: FetchContent() downloads this repo into build/_deps/utl-src together with corresponding documentation, which can be used offline since UTL docs are mostly written in standard markdown with relative links. Some things like badges might link to a repo, but most relevant content stays available.