[cxx-interop] Provide overlay for std::wstring
#83943
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This adds CxxStdlib overlay features to `std::wstring` similarly to `std::string`, `std::u16string`, etc. This lets clients e.g. convert between Swift String and C++ wide string simply by calling an initializer. rdar://159272493
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@swift-ci please test |
j-hui
approved these changes
Aug 27, 2025
Xazax-hun
reviewed
Aug 27, 2025
| public init(_ string: String) { | ||
| self.init() | ||
| #if os(Windows) | ||
| for char in string.utf16 { |
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Would relying on something like string.withCString(encodedAs: UTF16.self) be more efficient?
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Quite possibly, yes, although this is copied verbatim from the std::u16string constructor, so I think we should update both constructors in a separate PR.
| @@ -95,6 +95,30 @@ extension std.u32string { | |||
| } | |||
| } | |||
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| extension std.wstring { | |||
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I wonder if it would make sense auto conforming wstring to the corresponding u*string instead. Aren't they supposed to desugar to the same type?
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Nope, they are distinct types! wchar_t isn't the same type as char16_t or char32_t, even if the bitwidth matches.
Xazax-hun
approved these changes
Aug 27, 2025
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This adds CxxStdlib overlay features to
std::wstringsimilarly tostd::string,std::u16string, etc.This lets clients e.g. convert between Swift String and C++ wide string simply by calling an initializer.
rdar://159272493