# Abseil - C++ Common Libraries The repository contains the Abseil C++ library code. Abseil is an open-source collection of C++ code (compliant to C++11) designed to augment the C++ standard library. ## Table of Contents - [About Abseil](#about) - [Quickstart](#quickstart) - [Building Abseil](#build) - [Support](#support) - [Codemap](#codemap) - [Releases](#releases) - [License](#license) - [Links](#links) <a name="about"></a> ## About Abseil Abseil is an open-source collection of C++ library code designed to augment the C++ standard library. The Abseil library code is collected from Google's own C++ code base, has been extensively tested and used in production, and is the same code we depend on in our daily coding lives. In some cases, Abseil provides pieces missing from the C++ standard; in others, Abseil provides alternatives to the standard for special needs we've found through usage in the Google code base. We denote those cases clearly within the library code we provide you. Abseil is not meant to be a competitor to the standard library; we've just found that many of these utilities serve a purpose within our code base, and we now want to provide those resources to the C++ community as a whole. <a name="quickstart"></a> ## Quickstart If you want to just get started, make sure you at least run through the [Abseil Quickstart](https://abseil.io/docs/cpp/quickstart). The Quickstart contains information about setting up your development environment, downloading the Abseil code, running tests, and getting a simple binary working. <a name="build"></a> ## Building Abseil [Bazel](https://bazel.build) and [CMake](https://cmake.org/) are the official build systems for Abseil. See the [quickstart](https://abseil.io/docs/cpp/quickstart) for more information on building Abseil using the Bazel build system. If you require CMake support, please check the [CMake build instructions](CMake/README.md) and [CMake Quickstart](https://abseil.io/docs/cpp/quickstart-cmake). ## Support Abseil is officially supported on many platforms. See the [Abseil platform support guide](https://abseil.io/docs/cpp/platforms/platforms) for details on supported operating systems, compilers, CPUs, etc. ## Codemap Abseil contains the following C++ library components: * [`base`](absl/base/) Abseil Fundamentals <br /> The `base` library contains initialization code and other code which all other Abseil code depends on. Code within `base` may not depend on any other code (other than the C++ standard library). * [`algorithm`](absl/algorithm/) <br /> The `algorithm` library contains additions to the C++ `<algorithm>` library and container-based versions of such algorithms. * [`cleanup`](absl/cleanup/) <br /> The `cleanup` library contains the control-flow-construct-like type `absl::Cleanup` which is used for executing a callback on scope exit. * [`container`](absl/container/) <br /> The `container` library contains additional STL-style containers, including Abseil's unordered "Swiss table" containers. * [`debugging`](absl/debugging/) <br /> The `debugging` library contains code useful for enabling leak checks, and stacktrace and symbolization utilities. * [`hash`](absl/hash/) <br /> The `hash` library contains the hashing framework and default hash functor implementations for hashable types in Abseil. * [`memory`](absl/memory/) <br /> The `memory` library contains C++11-compatible versions of `std::make_unique()` and related memory management facilities. * [`meta`](absl/meta/) <br /> The `meta` library contains C++11-compatible versions of type checks available within C++14 and C++17 versions of the C++ `<type_traits>` library. * [`numeric`](absl/numeric/) <br /> The `numeric` library contains C++11-compatible 128-bit integers. * [`profiling`](absl/profiling/) <br /> The `profiling` library contains utility code for profiling C++ entities. It is currently a private dependency of other Abseil libraries. * [`status`](absl/status/) <br /> The `status` contains abstractions for error handling, specifically `absl::Status` and `absl::StatusOr<T>`. * [`strings`](absl/strings/) <br /> The `strings` library contains a variety of strings routines and utilities, including a C++11-compatible version of the C++17 `std::string_view` type. * [`synchronization`](absl/synchronization/) <br /> The `synchronization` library contains concurrency primitives (Abseil's `absl::Mutex` class, an alternative to `std::mutex`) and a variety of synchronization abstractions. * [`time`](absl/time/) <br /> The `time` library contains abstractions for computing with absolute points in time, durations of time, and formatting and parsing time within time zones. * [`types`](absl/types/) <br /> The `types` library contains non-container utility types, like a C++11-compatible version of the C++17 `std::optional` type. * [`utility`](absl/utility/) <br /> The `utility` library contains utility and helper code. ## Releases Abseil recommends users "live-at-head" (update to the latest commit from the master branch as often as possible). However, we realize this philosophy doesn't work for every project, so we also provide [Long Term Support Releases](https://github.com/abseil/abseil-cpp/releases) to which we backport fixes for severe bugs. See our [release management](https://abseil.io/about/releases) document for more details. ## License The Abseil C++ library is licensed under the terms of the Apache license. See [LICENSE](LICENSE) for more information. ## Links For more information about Abseil: * Consult our [Abseil Introduction](https://abseil.io/about/intro) * Read [Why Adopt Abseil](https://abseil.io/about/philosophy) to understand our design philosophy. * Peruse our [Abseil Compatibility Guarantees](https://abseil.io/about/compatibility) to understand both what we promise to you, and what we expect of you in return.