tmp/tmpx1ivpbjh/{from.md → to.md}
RENAMED
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@@ -1,11 +1,11 @@
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### [[input.output]]: input/output library <a id="diff.cpp17.input.output">[[diff.cpp17.input.output]]</a>
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**Change:** Character array extraction only takes array types.
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**Rationale:** Increase safety via preventing buffer overflow at compile
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time. **Effect on original feature:** Valid C++17 code may fail to
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-
compile in this
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``` cpp
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auto p = new char[100];
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char q[100];
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std::cin >> std::setw(20) >> p; // ill-formed; previously well-formed
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@@ -14,11 +14,12 @@ std::cin >> std::setw(20) >> q; // OK
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**Change:** Overload resolution for ostream inserters used with UTF-8
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literals. **Rationale:** Required for new features. **Effect on original
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feature:** Valid C++17 code that passes UTF-8 literals to
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`basic_ostream<char, ...>::operator<<` or
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-
`basic_ostream<wchar_t, ...>::operator<<` is now ill-formed.
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``` cpp
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std::cout << u8"text"; // previously called operator<<(const char*) and printed a string;
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// now ill-formed
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std::cout << u8'X'; // previously called operator<<(char) and printed a character;
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@@ -29,11 +30,12 @@ std::cout << u8'X'; // previously called operator<<(char) and printe
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`wchar_t`, `char16_t`, or `char32_t` types. **Rationale:** Removal of
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surprising behavior. **Effect on original feature:** Valid C++17 code
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that passes `wchar_t`, `char16_t`, or `char32_t` characters or strings
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to `basic_ostream<char, ...>::operator<<` or that passes `char16_t` or
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`char32_t` characters or strings to
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`basic_ostream<wchar_t, ...>::operator<<` is now ill-formed.
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``` cpp
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std::cout << u"text"; // previously formatted the string as a pointer value;
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// now ill-formed
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std::cout << u'X'; // previously formatted the character as an integer value;
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@@ -42,11 +44,12 @@ std::cout << u'X'; // previously formatted the character as an inte
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**Change:** Return type of filesystem path format observer member
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functions. **Rationale:** Required for new features. **Effect on
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original feature:** Valid C++17 code that depends on the `u8string()`
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and `generic_u8string()` member functions of `std::filesystem::path`
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returning `std::string` is not valid in this
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``` cpp
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std::filesystem::path p;
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std::string s1 = p.u8string(); // ill-formed; previously well-formed
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std::string s2 = p.generic_u8string(); // ill-formed; previously well-formed
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### [[input.output]]: input/output library <a id="diff.cpp17.input.output">[[diff.cpp17.input.output]]</a>
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**Change:** Character array extraction only takes array types.
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**Rationale:** Increase safety via preventing buffer overflow at compile
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time. **Effect on original feature:** Valid C++17 code may fail to
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+
compile in this revision of C++. For example:
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``` cpp
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auto p = new char[100];
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char q[100];
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std::cin >> std::setw(20) >> p; // ill-formed; previously well-formed
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**Change:** Overload resolution for ostream inserters used with UTF-8
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literals. **Rationale:** Required for new features. **Effect on original
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feature:** Valid C++17 code that passes UTF-8 literals to
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`basic_ostream<char, ...>::operator<<` or
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+
`basic_ostream<wchar_t, ...>::operator<<` is now ill-formed. For
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+
example:
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``` cpp
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std::cout << u8"text"; // previously called operator<<(const char*) and printed a string;
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// now ill-formed
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std::cout << u8'X'; // previously called operator<<(char) and printed a character;
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`wchar_t`, `char16_t`, or `char32_t` types. **Rationale:** Removal of
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surprising behavior. **Effect on original feature:** Valid C++17 code
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that passes `wchar_t`, `char16_t`, or `char32_t` characters or strings
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to `basic_ostream<char, ...>::operator<<` or that passes `char16_t` or
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`char32_t` characters or strings to
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+
`basic_ostream<wchar_t, ...>::operator<<` is now ill-formed. For
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+
example:
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``` cpp
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std::cout << u"text"; // previously formatted the string as a pointer value;
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// now ill-formed
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std::cout << u'X'; // previously formatted the character as an integer value;
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**Change:** Return type of filesystem path format observer member
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functions. **Rationale:** Required for new features. **Effect on
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original feature:** Valid C++17 code that depends on the `u8string()`
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and `generic_u8string()` member functions of `std::filesystem::path`
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+
returning `std::string` is not valid in this revision of C++. For
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+
example:
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``` cpp
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std::filesystem::path p;
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std::string s1 = p.u8string(); // ill-formed; previously well-formed
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std::string s2 = p.generic_u8string(); // ill-formed; previously well-formed
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