31d7bcc583
- At the AGM we formed an ad-hoc documentation working group. - One of our ideas was that we should have a last reviewed date for documentation, so that we can periodically implement a review mechanism (GitHub Actions posts to Slack for a regular documentation outdatedness check?) to track how old docs are and ensure they're still relevant. - This is a first step towards that goal, by adding a `last_review_date` to the metadata of all docs with a date of earlier than Homebrew's inception because everything needs reviewing so that we start from a good base!
33 lines
1.2 KiB
Markdown
33 lines
1.2 KiB
Markdown
---
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last_review_date: "1970-01-01"
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---
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# C++ Standard Libraries
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There are two C++ standard libraries supported by Apple compilers.
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The default for 10.9 and later is **libc++**, which is also the default for `clang` on older
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platforms when building C++11 code.
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The default for 10.8 and earlier was **libstdc++**, supported by Apple GCC
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compilers, GNU GCC compilers, and `clang`. This was marked deprecated with a
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warning during compilation as of Xcode 8.
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There are subtle incompatibilities between several of the C++ standard libraries,
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so Homebrew will refuse to install software if a dependency was built with an
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incompatible C++ library. It's recommended that you install the dependency tree
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using a compatible compiler.
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**If you've upgraded to 10.9 or later from an earlier version:** Because the default C++
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standard library is now libc++, you may not be able to build software using
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dependencies that you built on 10.8 or earlier. If you're reading this page because
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you were directed here by a build error, you can most likely fix the issue if
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you reinstall all the dependencies of the package you're trying to build.
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Example install using GCC 9:
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```sh
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brew install gcc@9
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brew install --cc=gcc-9 <formula>
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```
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