f1d21ef1c370898ae10569f2a8569bd98d71a981 doc: add C++17 release note for 0.21.0 (fanquake) Pull request description: TLDR: Mention that the codebase is now compatible with C++17, and that the intention is to require C++17 starting with 0.22.0. Following some discussion with Cory/Carl, and in #16684, I think this is the next step in the C++17 migration. While #16684 mentions a gitian/Guix release with C++17, it's not yet clear how that would be done. Are we just going to pass `--enable-c++17` in gitian/Guix?. Are we changing our default in configure.ac? According to the [last comment](https://github.com/bitcoin/bitcoin/issues/16684#issuecomment-643778757) in #16684, we wouldn't be changing anything in depends: > No, everything (including depends) will stay at C++11. However I don't think we want to be mixing C++11 built dependencies, with a C++17 built bitcoind, if there is any potential for compatibility issues. Instead, I'd suggest we build the 0.21.0 release as C++11, and do a complete switch to C++17 for 0.22.0. Also, if we actually wanted to use C++17 in depends for 0.21.0, we couldn't without breaking C++11 compat (Qt). See below. Here is a potential timeline/TODOs for the migration: Potential Timeline * 17 / 6 / 2020 - Today * Some time prior to split-off: * Confirm that compiling with C++17 works. * Confirm that C++11 compatibility has not been broken. * 1 / 11 / 2020 * [0.21.0 split off happens](https://github.com/bitcoin/bitcoin/issues/18947). * 2 / 11 / 2020 * Merge an "incompatible with C++11" change into master. * Switch configure to use C++17 mode by default. * Update minimum compiler requirements. At least: * Clang 5: https://clang.llvm.org/cxx_status.html#cxx17 * GCC 7: https://gcc.gnu.org/projects/cxx-status.html#cxx17 * While GCC has some support from 5, it seems a more complete support landed in GCC 7. * https://gcc.gnu.org/gcc-7/changes.html#cxx * Switch depends packages to use C++17 where applicable. * Bump Qt from 5.9.x (no c++17 mode) to, likely, 5.15.x (LTS). * Drop support for macOS < 10.14.x * The c++ dylib shipped with macOS [doesn't support c++17, prior to macOS 10.14](https://github.com/bitcoin/bitcoin/issues/16684#issuecomment-643722538). * Building Qt 5.12 or 5.15 in C++17 mode will also require a minimum macOS deployment target of 10.14. https://codereview.qt-project.org/c/qt/qtbase/+/283832. * Begin merging PRs like #19183 and #19245. * I've left some comments in #19183 if the macOS runtime issue interests anyone. * 3 / 12 / 2020 * 0.21.0 released. * Built as C++11. * Contains warning in release notes that compiling 0.22.0 will require C++17. * 3 / 6 / 2021 * 0.22.0 released. * Full of C++17 code. One thing worth noting, is that we cannot bump our Qt to a newer LTS for 0.21.0, without breaking C++11 compatibility. Qt 5.12 is not compilable in C++11 mode, as the project has started using C++14 features throughout at least the macOS portions of it's codebase, and seemingly "forgotten" that the release is meant to be C++11 compatible. Upstream bug here: https://bugreports.qt.io/browse/QTBUG-77310. > Building Qt requires C+11, at a minimum, but in practice we use later features, usually under a feature define, or with a fallback of some kind. On platforms that support > C11, we've (apparently) not considered the fallback necessary, under the assumption C+14 is always available. ACKs for top commit: MarcoFalke: ACK f1d21ef1c370898ae10569f2a8569bd98d71a981 can't hurt to give an advance warning Sjors: ACK f1d21ef1c370898ae10569f2a8569bd98d71a981 laanwj: ACK f1d21ef1c370898ae10569f2a8569bd98d71a981 theStack: ACK f1d21ef1c370898ae10569f2a8569bd98d71a981 Tree-SHA512: 706baceb07d9584783ba6e437cdf447531c20f586285b9797edc21f3adb1e9d386059d1c543c70eb298d0f8e555dafb6682a55d35c5836979fc12132e8ba06f5
Bitcoin Core
Setup
Bitcoin Core is the original Bitcoin client and it builds the backbone of the network. It downloads and, by default, stores the entire history of Bitcoin transactions, which requires a few hundred gigabytes of disk space. Depending on the speed of your computer and network connection, the synchronization process can take anywhere from a few hours to a day or more.
To download Bitcoin Core, visit bitcoincore.org.
Running
The following are some helpful notes on how to run Bitcoin Core on your native platform.
Unix
Unpack the files into a directory and run:
bin/bitcoin-qt
(GUI) orbin/bitcoind
(headless)
Windows
Unpack the files into a directory, and then run bitcoin-qt.exe.
macOS
Drag Bitcoin Core to your applications folder, and then run Bitcoin Core.
Need Help?
- See the documentation at the Bitcoin Wiki for help and more information.
- Ask for help on #bitcoin on Freenode. If you don't have an IRC client, use webchat here.
- Ask for help on the BitcoinTalk forums, in the Technical Support board.
Building
The following are developer notes on how to build Bitcoin Core on your native platform. They are not complete guides, but include notes on the necessary libraries, compile flags, etc.
- Dependencies
- macOS Build Notes
- Unix Build Notes
- Windows Build Notes
- FreeBSD Build Notes
- OpenBSD Build Notes
- NetBSD Build Notes
- Gitian Building Guide (External Link)
Development
The Bitcoin repo's root README contains relevant information on the development process and automated testing.
- Developer Notes
- Productivity Notes
- Release Notes
- Release Process
- Source Code Documentation (External Link)
- Translation Process
- Translation Strings Policy
- JSON-RPC Interface
- Unauthenticated REST Interface
- Shared Libraries
- BIPS
- Dnsseed Policy
- Benchmarking
Resources
- Discuss on the BitcoinTalk forums, in the Development & Technical Discussion board.
- Discuss project-specific development on #bitcoin-core-dev on Freenode. If you don't have an IRC client, use webchat here.
- Discuss general Bitcoin development on #bitcoin-dev on Freenode. If you don't have an IRC client, use webchat here.
Miscellaneous
- Assets Attribution
- bitcoin.conf Configuration File
- Files
- Fuzz-testing
- Reduce Memory
- Reduce Traffic
- Tor Support
- Init Scripts (systemd/upstart/openrc)
- ZMQ
- PSBT support
License
Distributed under the MIT software license.