1# Abseil - C++ Common Libraries 2 3The repository contains the Abseil C++ library code. Abseil is an open-source 4collection of C++ code (compliant to C++14) designed to augment the C++ 5standard library. 6 7## Table of Contents 8 9- [About Abseil](#about) 10- [Quickstart](#quickstart) 11- [Building Abseil](#build) 12- [Support](#support) 13- [Codemap](#codemap) 14- [Releases](#releases) 15- [License](#license) 16- [Links](#links) 17 18<a name="about"></a> 19## About Abseil 20 21Abseil is an open-source collection of C++ library code designed to augment 22the C++ standard library. The Abseil library code is collected from Google's 23own C++ code base, has been extensively tested and used in production, and 24is the same code we depend on in our daily coding lives. 25 26In some cases, Abseil provides pieces missing from the C++ standard; in 27others, Abseil provides alternatives to the standard for special needs 28we've found through usage in the Google code base. We denote those cases 29clearly within the library code we provide you. 30 31Abseil is not meant to be a competitor to the standard library; we've 32just found that many of these utilities serve a purpose within our code 33base, and we now want to provide those resources to the C++ community as 34a whole. 35 36<a name="quickstart"></a> 37## Quickstart 38 39If you want to just get started, make sure you at least run through the 40[Abseil Quickstart](https://abseil.io/docs/cpp/quickstart). The Quickstart 41contains information about setting up your development environment, downloading 42the Abseil code, running tests, and getting a simple binary working. 43 44<a name="build"></a> 45## Building Abseil 46 47[Bazel](https://bazel.build) and [CMake](https://cmake.org/) are the official 48build systems for Abseil. 49 50See the [quickstart](https://abseil.io/docs/cpp/quickstart) for more information 51on building Abseil using the Bazel build system. 52 53If you require CMake support, please check the [CMake build 54instructions](CMake/README.md) and [CMake 55Quickstart](https://abseil.io/docs/cpp/quickstart-cmake). 56 57## Support 58 59Abseil follows Google's [Foundational C++ Support 60Policy](https://opensource.google/documentation/policies/cplusplus-support). See 61[this 62table](https://github.com/google/oss-policies-info/blob/main/foundational-cxx-support-matrix.md) 63for a list of currently supported versions compilers, platforms, and build 64tools. 65 66## Codemap 67 68Abseil contains the following C++ library components: 69 70* [`base`](absl/base/) Abseil Fundamentals 71 <br /> The `base` library contains initialization code and other code which 72 all other Abseil code depends on. Code within `base` may not depend on any 73 other code (other than the C++ standard library). 74* [`algorithm`](absl/algorithm/) 75 <br /> The `algorithm` library contains additions to the C++ `<algorithm>` 76 library and container-based versions of such algorithms. 77* [`cleanup`](absl/cleanup/) 78 <br /> The `cleanup` library contains the control-flow-construct-like type 79 `absl::Cleanup` which is used for executing a callback on scope exit. 80* [`container`](absl/container/) 81 <br /> The `container` library contains additional STL-style containers, 82 including Abseil's unordered "Swiss table" containers. 83* [`debugging`](absl/debugging/) 84 <br /> The `debugging` library contains code useful for enabling leak 85 checks, and stacktrace and symbolization utilities. 86* [`hash`](absl/hash/) 87 <br /> The `hash` library contains the hashing framework and default hash 88 functor implementations for hashable types in Abseil. 89* [`memory`](absl/memory/) 90 <br /> The `memory` library contains memory management facilities that 91 augment C++'s `<memory>` library. 92* [`meta`](absl/meta/) 93 <br /> The `meta` library contains compatible versions of type checks 94 available within C++14 and C++17 versions of the C++ `<type_traits>` library. 95* [`numeric`](absl/numeric/) 96 <br /> The `numeric` library contains 128-bit integer types as well as 97 implementations of C++20's bitwise math functions. 98* [`profiling`](absl/profiling/) 99 <br /> The `profiling` library contains utility code for profiling C++ 100 entities. It is currently a private dependency of other Abseil libraries. 101* [`status`](absl/status/) 102 <br /> The `status` contains abstractions for error handling, specifically 103 `absl::Status` and `absl::StatusOr<T>`. 104* [`strings`](absl/strings/) 105 <br /> The `strings` library contains a variety of strings routines and 106 utilities, including a C++14-compatible version of the C++17 107 `std::string_view` type. 108* [`synchronization`](absl/synchronization/) 109 <br /> The `synchronization` library contains concurrency primitives (Abseil's 110 `absl::Mutex` class, an alternative to `std::mutex`) and a variety of 111 synchronization abstractions. 112* [`time`](absl/time/) 113 <br /> The `time` library contains abstractions for computing with absolute 114 points in time, durations of time, and formatting and parsing time within 115 time zones. 116* [`types`](absl/types/) 117 <br /> The `types` library contains non-container utility types, like a 118 C++14-compatible version of the C++17 `std::optional` type. 119* [`utility`](absl/utility/) 120 <br /> The `utility` library contains utility and helper code. 121 122## Releases 123 124Abseil recommends users "live-at-head" (update to the latest commit from the 125master branch as often as possible). However, we realize this philosophy doesn't 126work for every project, so we also provide [Long Term Support 127Releases](https://github.com/abseil/abseil-cpp/releases) to which we backport 128fixes for severe bugs. See our [release 129management](https://abseil.io/about/releases) document for more details. 130 131## License 132 133The Abseil C++ library is licensed under the terms of the Apache 134license. See [LICENSE](LICENSE) for more information. 135 136## Links 137 138For more information about Abseil: 139 140* Consult our [Abseil Introduction](https://abseil.io/about/intro) 141* Read [Why Adopt Abseil](https://abseil.io/about/philosophy) to understand our 142 design philosophy. 143* Peruse our 144 [Abseil Compatibility Guarantees](https://abseil.io/about/compatibility) to 145 understand both what we promise to you, and what we expect of you in return. 146