[libcxx-commits] [PATCH] D95821: [docs] Explain noexcept policy for narrow contracts.

[Zoe Carver via Phabricator via libcxx-commits]

zoecarver created this revision.
zoecarver added reviewers: mclow.lists, ldionne.
zoecarver requested review of this revision.
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Adds documentation around libc++'s policy to add noexcept to things that cannot throw but aren't marked as noexcept.

Refs LWG 3518 and D95251 <https://reviews.llvm.org/D95251>.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D95821

Files:
  libcxx/docs/UsingLibcxx.rst


Index: libcxx/docs/UsingLibcxx.rst
===================================================================
--- libcxx/docs/UsingLibcxx.rst
+++ libcxx/docs/UsingLibcxx.rst
@@ -346,3 +346,19 @@
 * ``unique``
 * ``upper_bound``
 * ``lock_guard``'s constructors
+
+.. _noexcept extension:
+
+Extended applications of ``noexcept``
+------------------------------------------
+
+As of version 14 libc++ will mark functions that do not throw (i.e.,
+"Throws: nothing" as ``noexcept``). This means that functions will not
+report precondition violations by throwing and user-provided functions,
+such as custom predicates or custom traits, which throw will not be
+propagated up to the caller (unless specified otherwise by the standard).
+
+Before version 14, libc++ did not specify whether a function that did not
+throw would be marked as ``noexcept``, so users should not rely on any
+non-throwing functions to be marked ``noexcept`` (unless the standard
+specifies it).
\ No newline at end of file


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