[libcxx-commits] [PATCH] D91778: [libc++] [P0966] [C++20] Fix bug PR45368 by correctly implementing P0966: string::reserve should not shrink.

[Louis Dionne via Phabricator via libcxx-commits]

ldionne added inline comments.


================
Comment at: libcxx/include/string:3273-3276
+#if _LIBCPP_STD_VER > 17
+    // Reserve never shrinks as of C++20.
+    if (__requested_capacity <= capacity()) return;
+#endif
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rsmith wrote:
> This `#if` doesn't seem to work: because `reserve(size_type)` is not inline, we always use the version from the libc++ library, which means we get the C++17 behavior if the library was built in C++17 mode, and we get the C++20 behavior if the library was built in C++20 mode, regardless of the standard mode used by the compilation using libc++.
Oh crap, that's right. Nice catch. But I'm not seeing a way to fix this except to make this function inline, and to keep a definition in the dylib for backwards compatibility (but nobody except already-compiled code would call it). Do you see other ways?


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https://reviews.llvm.org/D91778