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The repository contains the Abseil C++ library code. Abseil is an open-sourcecollection of C++ code (compliant to C++17) designed to augment the C++standard library.

• About Abseil
• Quickstart
• Building Abseil
• Support
• Codemap
• Releases
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Abseil is an open-source collection of C++ library code designed to augmentthe C++ standard library. The Abseil library code is collected from Google'sown C++ code base, has been extensively tested and used in production, andis the same code we depend on in our daily coding lives.

In some cases, Abseil provides pieces missing from the C++ standard; inothers, Abseil provides alternatives to the standard for special needswe've found through usage in the Google code base. We denote those casesclearly within the library code we provide you.

Abseil is not meant to be a competitor to the standard library; we'vejust found that many of these utilities serve a purpose within our codebase, and we now want to provide those resources to the C++ community asa whole.

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

Bazel andCMake are the officialbuild systems for Abseil.See thequickstart for more informationon building Abseil using the Bazel build system.If you require CMake support, please check theCMake buildinstructions andCMakeQuickstart.

Abseil follows Google'sFoundational C++ SupportPolicy. Seethistablefor a list of currently supported versions compilers, platforms, and buildtools.

Abseil contains the following C++ library components:

• base
  Thebase library contains initialization code and other code whichall other Abseil code depends on. Code withinbase may not depend on anyother code (other than the C++ standard library).
• algorithm
  Thealgorithm library contains additions to the C++<algorithm>library and container-based versions of such algorithms.
• cleanup
  Thecleanup library contains the control-flow-construct-like typeabsl::Cleanup which is used for executing a callback on scope exit.
• container
  Thecontainer library contains additional STL-style containers,including Abseil's unordered "Swiss table" containers.
• crc Thecrc library contains code forcomputing error-detecting cyclic redundancy checks on data.
• debugging
  Thedebugging library contains code useful for enabling leakchecks, and stacktrace and symbolization utilities.
• flags
  Theflags library contains code for handling command line flags forlibraries and binaries built with Abseil.
• hash
  Thehash library contains the hashing framework and default hashfunctor implementations for hashable types in Abseil.
• log
  Thelog library containsLOG andCHECK macros and facilitiesfor writing logged messages out to disk,stderr, or user-extensibledestinations.
• memory
  Thememory library contains memory management facilities that augmentC++'s<memory> library.
• meta
  Themeta library contains type checkssimilar to those available in the C++<type_traits> library.
• numeric
  Thenumeric library contains 128-bit integer types as well asimplementations of C++20's bitwise math functions.
• profiling
  Theprofiling library contains utility code for profiling C++entities. It is currently a private dependency of other Abseil libraries.
• random
  Therandom library contains functions for generating pseudorandomvalues.
• status
  Thestatus library contains abstractions for error handling,specificallyabsl::Status andabsl::StatusOr<T>.
• strings
  Thestrings library contains a variety of strings routines andutilities.
• synchronization
  Thesynchronization library contains concurrency primitives (Abseil'sabsl::Mutex class, an alternative tostd::mutex) and a variety ofsynchronization abstractions.
• time
  Thetime library contains abstractions for computing with absolutepoints in time, durations of time, and formatting and parsing time withintime zones.
• types
  Thetypes library contains non-container utility types.
• utility
  Theutility library contains utility and helper code.

Abseil recommends users "live-at-head" (update to the latest commit from themaster branch as often as possible). However, we realize this philosophy doesn'twork for every project, so we also provideLong Term SupportReleases to which we backportfixes for severe bugs. See ourreleasemanagement document for more details.

The Abseil C++ library is licensed under the terms of the Apachelicense. SeeLICENSE for more information.

For more information about Abseil:

• Consult ourAbseil Introduction
• ReadWhy Adopt Abseil to understand ourdesign philosophy.
• Peruse ourAbseil Compatibility Guarantees tounderstand both what we promise to you, and what we expect of you in return.