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authorAbseil Team <absl-team@google.com>2017-10-05T20·33-0700
committervslashg <gfalcon@google.com>2017-10-05T20·55-0400
commitd732f2014bdd141135e6af06ee5b47e7fbe4b877 (patch)
treedd5083fd1250b9300d2cfa19e862efc455c18fbe /absl/types/optional.h
parentcc4bed2d74f7c8717e31f9579214ab52a9c9c610 (diff)
Changes imported from Abseil "staging" branch:
  - d5a5960a133967e4af02836d304884cd6cbd6e46 Adjusting time tests for flakiness by Gennadiy Civil <misterg@google.com>
  - ccb8535fdc92c3c99bfa2795e75d3fbdcb134571 Internal-only tweak. by Jorg Brown <jorg@google.com>
  - 4c03dd9e54bd4645e7e7a8dfb3c590f5b0654884 Fix comment on some C++11 type traits backport. by Xiaoyi Zhang <zhangxy@google.com>
  - 43cd12d2304464163e33ae932fbb842a869213dd Allow intrinsic int128 to be set for __ppc64__ targets. by Abseil Team <absl-team@google.com>
  - 789e9c13de67ef3c7ba09c765c3484621897b6bb Update README.md description of 'types' library to be con... by Abseil Team <absl-team@google.com>
  - 8be10d7683c90b85244ddc67360a7ca2dfffdf01 Update comment on move constructors' noexcept specificati... by Xiaoyi Zhang <zhangxy@google.com>

GitOrigin-RevId: d5a5960a133967e4af02836d304884cd6cbd6e46
Change-Id: I743efee47b9e65f46a44d9ab80ccd62cfd0c1301
Diffstat (limited to 'absl/types/optional.h')
-rw-r--r--absl/types/optional.h7
1 files changed, 7 insertions, 0 deletions
diff --git a/absl/types/optional.h b/absl/types/optional.h
index f1b41ace8195..e952a04aa90c 100644
--- a/absl/types/optional.h
+++ b/absl/types/optional.h
@@ -118,6 +118,13 @@ namespace absl {
 //      and `is_nothrow_swappable()` is the same as `std::is_trivial()`.
 //    * `make_optional()` cannot be declared `constexpr` due to the absence of
 //      guaranteed copy elision.
+//    * The move constructor's `noexcept` specification is stronger, i.e. if the
+//      default allocator is non-throwing (via setting
+//      `ABSL_ALLOCATOR_NOTHROW`), it evaluates to `noexcept(true)`, because
+//      we assume
+//       a) move constructors should only throw due to allocation failure and
+//       b) if T's move constructor allocates, it uses the same allocation
+//          function as the default allocator.
 template <typename T>
 class optional;