[istream] - C++17 → C++20

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tmp/tmpjdkyim_c/{from.md → to.md} +27 -32

tmp/tmpjdkyim_c/{from.md → to.md} RENAMED Viewed

@@ -3,22 +3,22 @@
 ``` cpp
 namespace std {
   template<class charT, class traits = char_traits<charT>>
   class basic_istream : virtual public basic_ios<charT, traits> {
   public:
-    // types (inherited from basic_ios ([ios])):
     using char_type   = charT;
     using int_type    = typename traits::int_type;
     using pos_type    = typename traits::pos_type;
     using off_type    = typename traits::off_type;
     using traits_type = traits;
     // [istream.cons], constructor/destructor
     explicit basic_istream(basic_streambuf<charT, traits>* sb);
     virtual ~basic_istream();
-    // [istream::sentry], prefix/suffix
     class sentry;
     // [istream.formatted], formatted input
     basic_istream<charT, traits>&
       operator>>(basic_istream<charT, traits>& (*pf)(basic_istream<charT, traits>&));
@@ -68,15 +68,15 @@ namespace std {
     basic_istream<charT, traits>& seekg(pos_type);
     basic_istream<charT, traits>& seekg(off_type, ios_base::seekdir);
   protected:
     // [istream.cons], copy/move constructor
-    basic_istream(const basic_istream& rhs) = delete;
     basic_istream(basic_istream&& rhs);
     // [istream.assign], assign and swap
-    basic_istream& operator=(const basic_istream& rhs) = delete;
     basic_istream& operator=(basic_istream&& rhs);
     void swap(basic_istream& rhs);
   };
   // [istream.extractors], character extraction templates
@@ -85,16 +85,16 @@ namespace std {
   template<class traits>
     basic_istream<char, traits>& operator>>(basic_istream<char, traits>&, unsigned char&);
   template<class traits>
     basic_istream<char, traits>& operator>>(basic_istream<char, traits>&, signed char&);
-  template<class charT, class traits>
-    basic_istream<charT, traits>& operator>>(basic_istream<charT, traits>&, charT*);
-  template<class traits>
-    basic_istream<char, traits>& operator>>(basic_istream<char, traits>&, unsigned char*);
-  template<class traits>
-    basic_istream<char, traits>& operator>>(basic_istream<char, traits>&, signed char*);
 }
 ```
 The class template `basic_istream` defines a number of member function
 signatures that assist in reading and interpreting input from sequences
@@ -107,72 +107,67 @@ obtain (or *extract*) input *characters* by calling `rdbuf()->sbumpc()`
 or `rdbuf()->sgetc()`. They may use other public members of `istream`.
 If `rdbuf()->sbumpc()` or `rdbuf()->sgetc()` returns `traits::eof()`,
 then the input function, except as explicitly noted otherwise, completes
 its actions and does `setstate(eofbit)`, which may throw
-`ios_base::failure` ([[iostate.flags]]), before returning.
 If one of these called functions throws an exception, then unless
-explicitly noted otherwise, the input function sets `badbit` in error
-state. If `badbit` is on in `exceptions()`, the input function rethrows
-the exception without completing its actions, otherwise it does not
-throw anything and proceeds as if the called function had returned a
 failure indication.
-##### `basic_istream` constructors <a id="istream.cons">[[istream.cons]]</a>
 ``` cpp
 explicit basic_istream(basic_streambuf<charT, traits>* sb);
 ```
-*Effects:* Constructs an object of class `basic_istream`, initializing
-the base class subobject with
-`basic_ios::init(sb)` ([[basic.ios.cons]]).
-*Postconditions:* `gcount() == 0`.
 ``` cpp
 basic_istream(basic_istream&& rhs);
 ```
-*Effects:* Move constructs from the rvalue `rhs`. This is accomplished
-by default constructing the base class, copying the `gcount()` from
-`rhs`, calling `basic_ios<charT, traits>::move(rhs)` to initialize the
-base class, and setting the `gcount()` for `rhs` to 0.
 ``` cpp
 virtual ~basic_istream();
 ```
-*Effects:* Destroys an object of class `basic_istream`.
 *Remarks:* Does not perform any operations of `rdbuf()`.
-##### Class `basic_istream` assign and swap <a id="istream.assign">[[istream.assign]]</a>
 ``` cpp
 basic_istream& operator=(basic_istream&& rhs);
 ```
-*Effects:* As if by `swap(rhs)`.
 *Returns:* `*this`.
 ``` cpp
 void swap(basic_istream& rhs);
 ```
 *Effects:* Calls `basic_ios<charT, traits>::swap(rhs)`. Exchanges the
 values returned by `gcount()` and `rhs.gcount()`.
-##### Class `basic_istream::sentry` <a id="istream::sentry">[[istream::sentry]]</a>
 ``` cpp
 namespace std {
   template<class charT, class traits = char_traits<charT>>
   class basic_istream<charT, traits>::sentry {
-    using traits_type = traits;
     bool ok_;                   // exposition only
   public:
     explicit sentry(basic_istream<charT, traits>& is, bool noskipws = false);
     ~sentry();
     explicit operator bool() const { return ok_; }
@@ -223,11 +218,11 @@ if (ctype.is(ctype.space, c) != 0)
 ```
 If, after any preparation is completed, `is.good()` is `true`,
 `ok_ != false` otherwise, `ok_ == false`. During preparation, the
 constructor may call `setstate(failbit)` (which may throw
-`ios_base::failure` ([[iostate.flags]]))[^19]
 ``` cpp
 ~sentry();
 ```
@@ -235,7 +230,7 @@ constructor may call `setstate(failbit)` (which may throw
 ``` cpp
 explicit operator bool() const;
 ```
-*Effects:* Returns `ok_`.

 ``` cpp
 namespace std {
   template<class charT, class traits = char_traits<charT>>
   class basic_istream : virtual public basic_ios<charT, traits> {
   public:
+    // types (inherited from basic_ios[ios])
     using char_type   = charT;
     using int_type    = typename traits::int_type;
     using pos_type    = typename traits::pos_type;
     using off_type    = typename traits::off_type;
     using traits_type = traits;
     // [istream.cons], constructor/destructor
     explicit basic_istream(basic_streambuf<charT, traits>* sb);
     virtual ~basic_istream();
+    // [istream.sentry], prefix/suffix
     class sentry;
     // [istream.formatted], formatted input
     basic_istream<charT, traits>&
       operator>>(basic_istream<charT, traits>& (*pf)(basic_istream<charT, traits>&));
     basic_istream<charT, traits>& seekg(pos_type);
     basic_istream<charT, traits>& seekg(off_type, ios_base::seekdir);
   protected:
     // [istream.cons], copy/move constructor
+    basic_istream(const basic_istream&) = delete;
     basic_istream(basic_istream&& rhs);
     // [istream.assign], assign and swap
+    basic_istream& operator=(const basic_istream&) = delete;
     basic_istream& operator=(basic_istream&& rhs);
     void swap(basic_istream& rhs);
   };
   // [istream.extractors], character extraction templates
   template<class traits>
     basic_istream<char, traits>& operator>>(basic_istream<char, traits>&, unsigned char&);
   template<class traits>
     basic_istream<char, traits>& operator>>(basic_istream<char, traits>&, signed char&);
+  template<class charT, class traits, size_t N>
+    basic_istream<charT, traits>& operator>>(basic_istream<charT, traits>&, charT(&)[N]);
+  template<class traits, size_t N>
+    basic_istream<char, traits>& operator>>(basic_istream<char, traits>&, unsigned char(&)[N]);
+  template<class traits, size_t N>
+    basic_istream<char, traits>& operator>>(basic_istream<char, traits>&, signed char(&)[N]);
 }
 ```
 The class template `basic_istream` defines a number of member function
 signatures that assist in reading and interpreting input from sequences
 or `rdbuf()->sgetc()`. They may use other public members of `istream`.
 If `rdbuf()->sbumpc()` or `rdbuf()->sgetc()` returns `traits::eof()`,
 then the input function, except as explicitly noted otherwise, completes
 its actions and does `setstate(eofbit)`, which may throw
+`ios_base::failure` [[iostate.flags]], before returning.
 If one of these called functions throws an exception, then unless
+explicitly noted otherwise, the input function sets `badbit` in the
+error state. If `badbit` is set in `exceptions()`, the input function
+rethrows the exception without completing its actions, otherwise it does
+not throw anything and proceeds as if the called function had returned a
 failure indication.
+##### Constructors <a id="istream.cons">[[istream.cons]]</a>
 ``` cpp
 explicit basic_istream(basic_streambuf<charT, traits>* sb);
 ```
+*Effects:* Initializes the base class subobject with
+`basic_ios::init(sb)` [[basic.ios.cons]].
+*Ensures:* `gcount() == 0`.
 ``` cpp
 basic_istream(basic_istream&& rhs);
 ```
+*Effects:* Default constructs the base class, copies the `gcount()` from
+`rhs`, calls `basic_ios<charT, traits>::move(rhs)` to initialize the
+base class, and sets the `gcount()` for `rhs` to 0.
 ``` cpp
 virtual ~basic_istream();
 ```
 *Remarks:* Does not perform any operations of `rdbuf()`.
+##### Assignment and swap <a id="istream.assign">[[istream.assign]]</a>
 ``` cpp
 basic_istream& operator=(basic_istream&& rhs);
 ```
+*Effects:* Equivalent to: `swap(rhs)`.
 *Returns:* `*this`.
 ``` cpp
 void swap(basic_istream& rhs);
 ```
 *Effects:* Calls `basic_ios<charT, traits>::swap(rhs)`. Exchanges the
 values returned by `gcount()` and `rhs.gcount()`.
+##### Class `basic_istream::sentry` <a id="istream.sentry">[[istream.sentry]]</a>
 ``` cpp
 namespace std {
   template<class charT, class traits = char_traits<charT>>
   class basic_istream<charT, traits>::sentry {
     bool ok_;                   // exposition only
   public:
     explicit sentry(basic_istream<charT, traits>& is, bool noskipws = false);
     ~sentry();
     explicit operator bool() const { return ok_; }
 ```
 If, after any preparation is completed, `is.good()` is `true`,
 `ok_ != false` otherwise, `ok_ == false`. During preparation, the
 constructor may call `setstate(failbit)` (which may throw
+`ios_base::failure` [[iostate.flags]]).[^19]
 ``` cpp
 ~sentry();
 ```
 ``` cpp
 explicit operator bool() const;
 ```
+*Returns:* `ok_`.

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