[stream.buffers] - C++20 → C++23

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tmp/tmpey4qpc0r/{from.md → to.md} +32 -29

tmp/tmpey4qpc0r/{from.md → to.md} RENAMED Viewed

@@ -65,10 +65,12 @@ above:
   shall have a defined value and is the next element to read (to get, or
   to obtain a character value, from the sequence).
 ### Class template `basic_streambuf` <a id="streambuf">[[streambuf]]</a>
 ``` cpp
 namespace std {
   template<class charT, class traits = char_traits<charT>>
   class basic_streambuf {
   public:
@@ -172,15 +174,15 @@ for deriving various *stream buffers* whose objects each control two
 ``` cpp
 basic_streambuf();
 ```
-*Effects:* Initializes:[^13]
 - all pointer member objects to null pointers,
-- the `getloc()` member to a copy the global locale, `locale()`, at the
-  time of construction.
 *Remarks:* Once the `getloc()` member is initialized, results of calling
 locale member functions, and of members of facets so obtained, can
 safely be cached until the next time the member `imbue` is called.
@@ -449,11 +451,11 @@ functions and to members of facets so obtained.
 basic_streambuf* setbuf(char_type* s, streamsize n);
 ```
 *Effects:* Influences stream buffering in a way that is defined
 separately for each class derived from `basic_streambuf` in this
-Clause ([[stringbuf.virtuals]], [[filebuf.virtuals]]).
 *Default behavior:* Does nothing. Returns `this`.
 ``` cpp
 pos_type seekoff(off_type off, ios_base::seekdir way,
@@ -461,12 +463,12 @@ pos_type seekoff(off_type off, ios_base::seekdir way,
                   = ios_base::in | ios_base::out);
 ```
 *Effects:* Alters the stream positions within one or more of the
 controlled sequences in a way that is defined separately for each class
-derived from `basic_streambuf` in this Clause ([[stringbuf.virtuals]],
-[[filebuf.virtuals]]).
 *Default behavior:* Returns `pos_type(off_type(-1))`.
 ``` cpp
 pos_type seekpos(pos_type sp,
@@ -474,12 +476,12 @@ pos_type seekpos(pos_type sp,
                   = ios_base::in | ios_base::out);
 ```
 *Effects:* Alters the stream positions within one or more of the
 controlled sequences in a way that is defined separately for each class
-derived from `basic_streambuf` in this Clause ([[stringbuf]],
-[[filebuf]]).
 *Default behavior:* Returns `pos_type(off_type(-1))`.
 ``` cpp
 int sync();
@@ -496,14 +498,15 @@ each derived class [[filebuf.virtuals]].
 *Default behavior:* Returns zero.
 ##### Get area <a id="streambuf.virt.get">[[streambuf.virt.get]]</a>
 ``` cpp
-streamsize showmanyc();\footnote{The morphemes of showmanyc\
-are ``es-how-many-see'', not ``show-manic''.}
 ```
 *Returns:* An estimate of the number of characters available in the
 sequence, or -1. If it returns a positive value, then successive calls
 to `underflow()` will not return `traits::eof()` until at least that
 number of characters have been extracted from the stream. If
 `showmanyc()` returns -1, then calls to `underflow()` or `uflow()` will
@@ -529,18 +532,10 @@ to `sbumpc()` would return `traits::eof()`.
 ``` cpp
 int_type underflow();
 ```
-*Remarks:* The public members of `basic_streambuf` call this virtual
-function only if `gptr()` is null or `gptr() >= egptr()`.
-*Returns:* `traits::to_int_type(c)`, where `c` is the first *character*
-of the *pending sequence*, without moving the input sequence position
-past it. If the pending sequence is null then the function returns
-`traits::eof()` to indicate failure.
 The *pending sequence* of characters is defined as the concatenation of
 - the empty sequence if `gptr()` is null, otherwise the characters in
   \[`gptr()`, `egptr()`), followed by
 - some (possibly empty) sequence of characters read from the input
@@ -566,12 +561,20 @@ that either
   in which case the characters in \[`eback()`, `gptr()`) agree with the
   last `gptr() - eback()` characters of the backup sequence, or
 - the characters in \[`gptr() - n`, `gptr()`) agree with the backup
   sequence (where `n` is the length of the backup sequence).
 *Default behavior:* Returns `traits::eof()`.
 ``` cpp
 int_type uflow();
 ```
 *Preconditions:* The constraints are the same as for `underflow()`,
@@ -579,26 +582,21 @@ except that the result character is transferred from the pending
 sequence to the backup sequence, and the pending sequence is not empty
 before the transfer.
 *Default behavior:* Calls `underflow()`. If `underflow()` returns
 `traits::eof()`, returns `traits::eof()`. Otherwise, returns the value
-of `traits::to_int_type(*gptr())` and increment the value of the next
 pointer for the input sequence.
 *Returns:* `traits::eof()` to indicate failure.
 ##### Putback <a id="streambuf.virt.pback">[[streambuf.virt.pback]]</a>
 ``` cpp
 int_type pbackfail(int_type c = traits::eof());
 ```
-*Remarks:* The public functions of `basic_streambuf` call this virtual
-function only when `gptr()` is null, `gptr() == eback()`, or
-`traits::eq(traits::to_char_type(c), gptr()[-1])` returns `false`. Other
-calls shall also satisfy that constraint.
 The *pending sequence* is defined as for `underflow()`, with the
 modifications that
 - If `traits::eq_int_type(c, traits::eof())` returns `true`, then the
   input sequence is backed up one character before the pending sequence
@@ -610,17 +608,22 @@ modifications that
 *Ensures:* On return, the constraints of `gptr()`, `eback()`, and
 `pptr()` are the same as for `underflow()`.
 *Returns:* `traits::eof()` to indicate failure. Failure may occur
 because the input sequence could not be backed up, or if for some other
-reason the pointers could not be set consistent with the constraints.
 `pbackfail()` is called only when put back has really failed.
 Returns some value other than `traits::eof()` to indicate success.
 *Default behavior:* Returns `traits::eof()`.
 ##### Put area <a id="streambuf.virt.put">[[streambuf.virt.put]]</a>
 ``` cpp
 streamsize xsputn(const char_type* s, streamsize n);
 ```
@@ -646,14 +649,10 @@ of
 - the empty sequence if `pbase()` is null, otherwise the
   `pptr() - pbase()` characters beginning at `pbase()`, followed by
 - the empty sequence if `traits::eq_int_type(c, traits::eof())` returns
   `true`, otherwise the sequence consisting of `c`.
-*Remarks:* The member functions `sputc()` and `sputn()` call this
-function in case that no room can be found in the put buffer enough to
-accommodate the argument character sequence.
 *Preconditions:* Every overriding definition of this virtual function
 obeys the following constraints:
 - The effect of consuming a character on the associated output sequence
   is specified.[^16]
@@ -673,5 +672,9 @@ obeys the following constraints:
 Otherwise, returns some value other than `traits::eof()` to indicate
 success.[^17]
 *Default behavior:* Returns `traits::eof()`.

   shall have a defined value and is the next element to read (to get, or
   to obtain a character value, from the sequence).
 ### Class template `basic_streambuf` <a id="streambuf">[[streambuf]]</a>
+#### General <a id="streambuf.general">[[streambuf.general]]</a>
 ``` cpp
 namespace std {
   template<class charT, class traits = char_traits<charT>>
   class basic_streambuf {
   public:
 ``` cpp
 basic_streambuf();
 ```
+*Effects:* Initializes:[^12]
 - all pointer member objects to null pointers,
+- the `getloc()` member to a copy of the global locale, `locale()`, at
+ the time of construction.
 *Remarks:* Once the `getloc()` member is initialized, results of calling
 locale member functions, and of members of facets so obtained, can
 safely be cached until the next time the member `imbue` is called.
 basic_streambuf* setbuf(char_type* s, streamsize n);
 ```
 *Effects:* Influences stream buffering in a way that is defined
 separately for each class derived from `basic_streambuf` in this
+Clause [[stringbuf.virtuals]], [[filebuf.virtuals]].
 *Default behavior:* Does nothing. Returns `this`.
 ``` cpp
 pos_type seekoff(off_type off, ios_base::seekdir way,
                   = ios_base::in | ios_base::out);
 ```
 *Effects:* Alters the stream positions within one or more of the
 controlled sequences in a way that is defined separately for each class
+derived from `basic_streambuf` in this
+Clause [[stringbuf.virtuals]], [[filebuf.virtuals]].
 *Default behavior:* Returns `pos_type(off_type(-1))`.
 ``` cpp
 pos_type seekpos(pos_type sp,
                   = ios_base::in | ios_base::out);
 ```
 *Effects:* Alters the stream positions within one or more of the
 controlled sequences in a way that is defined separately for each class
+derived from `basic_streambuf` in this
+Clause [[stringbuf]], [[filebuf]].
 *Default behavior:* Returns `pos_type(off_type(-1))`.
 ``` cpp
 int sync();
 *Default behavior:* Returns zero.
 ##### Get area <a id="streambuf.virt.get">[[streambuf.virt.get]]</a>
 ``` cpp
+streamsize showmanyc();
 ```
+[^13]
 *Returns:* An estimate of the number of characters available in the
 sequence, or -1. If it returns a positive value, then successive calls
 to `underflow()` will not return `traits::eof()` until at least that
 number of characters have been extracted from the stream. If
 `showmanyc()` returns -1, then calls to `underflow()` or `uflow()` will
 ``` cpp
 int_type underflow();
 ```
 The *pending sequence* of characters is defined as the concatenation of
 - the empty sequence if `gptr()` is null, otherwise the characters in
   \[`gptr()`, `egptr()`), followed by
 - some (possibly empty) sequence of characters read from the input
   in which case the characters in \[`eback()`, `gptr()`) agree with the
   last `gptr() - eback()` characters of the backup sequence, or
 - the characters in \[`gptr() - n`, `gptr()`) agree with the backup
   sequence (where `n` is the length of the backup sequence).
+*Returns:* `traits::to_int_type(c)`, where `c` is the first *character*
+of the *pending sequence*, without moving the input sequence position
+past it. If the pending sequence is null then the function returns
+`traits::eof()` to indicate failure.
 *Default behavior:* Returns `traits::eof()`.
+*Remarks:* The public members of `basic_streambuf` call this virtual
+function only if `gptr()` is null or `gptr() >= egptr()`.
 ``` cpp
 int_type uflow();
 ```
 *Preconditions:* The constraints are the same as for `underflow()`,
 sequence to the backup sequence, and the pending sequence is not empty
 before the transfer.
 *Default behavior:* Calls `underflow()`. If `underflow()` returns
 `traits::eof()`, returns `traits::eof()`. Otherwise, returns the value
+of `traits::to_int_type(*gptr())` and increments the value of the next
 pointer for the input sequence.
 *Returns:* `traits::eof()` to indicate failure.
 ##### Putback <a id="streambuf.virt.pback">[[streambuf.virt.pback]]</a>
 ``` cpp
 int_type pbackfail(int_type c = traits::eof());
 ```
 The *pending sequence* is defined as for `underflow()`, with the
 modifications that
 - If `traits::eq_int_type(c, traits::eof())` returns `true`, then the
   input sequence is backed up one character before the pending sequence
 *Ensures:* On return, the constraints of `gptr()`, `eback()`, and
 `pptr()` are the same as for `underflow()`.
 *Returns:* `traits::eof()` to indicate failure. Failure may occur
 because the input sequence could not be backed up, or if for some other
+reason the pointers cannot be set consistent with the constraints.
 `pbackfail()` is called only when put back has really failed.
 Returns some value other than `traits::eof()` to indicate success.
 *Default behavior:* Returns `traits::eof()`.
+*Remarks:* The public functions of `basic_streambuf` call this virtual
+function only when `gptr()` is null, `gptr() == eback()`, or
+`traits::eq(traits::to_char_type(c), gptr()[-1])` returns `false`. Other
+calls shall also satisfy that constraint.
 ##### Put area <a id="streambuf.virt.put">[[streambuf.virt.put]]</a>
 ``` cpp
 streamsize xsputn(const char_type* s, streamsize n);
 ```
 - the empty sequence if `pbase()` is null, otherwise the
   `pptr() - pbase()` characters beginning at `pbase()`, followed by
 - the empty sequence if `traits::eq_int_type(c, traits::eof())` returns
   `true`, otherwise the sequence consisting of `c`.
 *Preconditions:* Every overriding definition of this virtual function
 obeys the following constraints:
 - The effect of consuming a character on the associated output sequence
   is specified.[^16]
 Otherwise, returns some value other than `traits::eof()` to indicate
 success.[^17]
 *Default behavior:* Returns `traits::eof()`.
+*Remarks:* The member functions `sputc()` and `sputn()` call this
+function in case that no room can be found in the put buffer enough to
+accommodate the argument character sequence.

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