PR #1715: Generate options.h using CMake only once

Imported from GitHub PR https://github.com/abseil/abseil-cpp/pull/1715

Using abseil via CMake ExternalProject, for each compilation abseil is reconfigured. This leads to a new options-pinned.h generated and then a new options.h installed. Because of that new options.h file, all projects depending on abseil recompile entirely.

Using file(GENERATE ...) instead of file(WRITE ...) allows generating options-pinned.h only when the content is new or changed.

Merge b3b53860d1f6cc83283806117cd5d341159b6052 into cd75cb4ae32c46c84cef9a9c78b42174f22ed0ac

Merging this change closes #1715

COPYBARA_INTEGRATE_REVIEW=https://github.com/abseil/abseil-cpp/pull/1715 from BotellaA:patch-1 b3b53860d1f6cc83283806117cd5d341159b6052
PiperOrigin-RevId: 652495570
Change-Id: Ib14bd9a78f80a540aae73d7a94cb46e2c05e8509
1 file changed
tree: 2031f5a4de180b0c6f983686bdaac9eb8b71dbf8
  1. .github/
  2. absl/
  3. ci/
  4. CMake/
  5. .clang-format
  6. .gitignore
  7. ABSEIL_ISSUE_TEMPLATE.md
  8. AUTHORS
  9. BUILD.bazel
  10. CMakeLists.txt
  11. conanfile.py
  12. CONTRIBUTING.md
  13. create_lts.py
  14. FAQ.md
  15. LICENSE
  16. MODULE.bazel
  17. PrivacyInfo.xcprivacy
  18. README.md
  19. UPGRADES.md
  20. WORKSPACE
  21. WORKSPACE.bzlmod
README.md

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

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: