Abseil - C++ Common Libraries

The repository contains the Abseil C++ library code. Abseil is an open-source collection of C++ code (compliant to C++14) designed to augment the C++ standard library.

Table of Contents

• About Abseil
• Quickstart
• Building Abseil
• Support
• Codemap
• Releases
• License
• Links

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.

Quickstart

If you want to just get started, make sure you at least run through the Abseil Quickstart. The Quickstart contains information about setting up your development environment, downloading the Abseil code, running tests, and getting a simple binary working.

Building Abseil

Bazel and CMake are the official build systems for Abseil. See the quickstart for more information on building Abseil using the Bazel build system. If you require CMake support, please check the CMake build instructions and CMake Quickstart.

Support

Abseil follows Google's Foundational C++ Support Policy. See this table for a list of currently supported versions compilers, platforms, and build tools.

Codemap

Abseil contains the following C++ library components:

• base 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 The algorithm library contains additions to the C++ <algorithm> library and container-based versions of such algorithms.
• cleanup The cleanup library contains the control-flow-construct-like type absl::Cleanup which is used for executing a callback on scope exit.
• container The container library contains additional STL-style containers, including Abseil's unordered "Swiss table" containers.
• crc The crc library contains code for computing error-detecting cyclic redundancy checks on data.
• debugging The debugging library contains code useful for enabling leak checks, and stacktrace and symbolization utilities.
• flags The flags library contains code for handling command line flags for libraries and binaries built with Abseil.
• hash The hash library contains the hashing framework and default hash functor implementations for hashable types in Abseil.
• log The log library contains LOG and CHECK macros and facilities for writing logged messages out to disk, stderr, or user-extensible destinations.
• memory The memory library contains memory management facilities that augment C++'s <memory> library.
• meta The meta library contains compatible versions of type checks available within C++14 and C++17 versions of the C++ <type_traits> library.
• numeric The numeric library contains 128-bit integer types as well as implementations of C++20's bitwise math functions.
• profiling The profiling library contains utility code for profiling C++ entities. It is currently a private dependency of other Abseil libraries.
• random The random library contains functions for generating psuedorandom values.
• status The status library contains abstractions for error handling, specifically absl::Status and absl::StatusOr<T>.
• strings The strings library contains a variety of strings routines and utilities, including a C++14-compatible version of the C++17 std::string_view type.
• synchronization The synchronization library contains concurrency primitives (Abseil's absl::Mutex class, an alternative to std::mutex) and a variety of synchronization abstractions.
• time The time library contains abstractions for computing with absolute points in time, durations of time, and formatting and parsing time within time zones.
• types The types library contains non-container utility types, like a C++14-compatible version of the C++17 std::optional type.
• utility 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 to which we backport fixes for severe bugs. See our release management document for more details.

License

The Abseil C++ library is licensed under the terms of the Apache license. See LICENSE for more information.

Links

For more information about Abseil:

• Consult our Abseil Introduction
• Read Why Adopt Abseil to understand our design philosophy.
• Peruse our Abseil Compatibility Guarantees to understand both what we promise to you, and what we expect of you in return.