[PATCH] D56997: Fix implementation of P0966 - string::reserve Should Not Shrink

[Eric Fiselier via Phabricator]

EricWF added inline comments.


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Comment at: include/string:963
 
-    void reserve(size_type __res_arg);
+    _LIBCPP_INLINE_VISIBILITY void reserve(size_type __res_arg);
     _LIBCPP_INLINE_VISIBILITY void __resize_default_init(size_type __n);
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This change is ABI breaking.

Previously `reserve` was explicitly instantiated in the dylib. After this change it is not.
I'll think more about what the best way to handle this is.


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Comment at: include/string:3147
     size_type __sz = size();
+#if _LIBCPP_STD_VER > 17
+    if (__res_arg <= __cap)
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I think we need to re-implement `shrink_to_fit`  after this change, since it is currently implemented as `reserve(0)`. 


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Comment at: include/string:3147
     size_type __sz = size();
+#if _LIBCPP_STD_VER > 17
+    if (__res_arg <= __cap)
----------------
EricWF wrote:
> I think we need to re-implement `shrink_to_fit`  after this change, since it is currently implemented as `reserve(0)`. 
Since the new behavior is also allowed prior to C++20, I wonder if it would be better to make this change unconditionally?


Repository:
  rCXX libc++

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D56997/new/

https://reviews.llvm.org/D56997