From Jason Turner

[ostream.formatted]

C++14 → C++17 8.3 KB 91 lines
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Archived: C++14 | C++17
Markdown: C++14 | C++17
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  1. tmp/tmp27vkfjsa/{from.md → to.md} +43 -42
tmp/tmp27vkfjsa/{from.md → to.md} RENAMED
@@ -6,11 +6,11 @@ Each formatted output function begins execution by constructing an
6
  object of class `sentry`. If this object returns `true` when converted
7
  to a value of type `bool`, the function endeavors to generate the
8
  requested output. If the generation fails, then the formatted output
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  function does `setstate(ios_base::failbit)`, which might throw an
10
  exception. If an exception is thrown during output, then `ios::badbit`
11
- is turned on[^32] in `*this`’s error state. If
12
  `(exceptions()&badbit) != 0` then the exception is rethrown. Whether or
13
  not an exception is thrown, the `sentry` object is destroyed before
14
  leaving the formatted output function. If no exception is thrown, the
15
  result of the formatted output function is `*this`.
16
 
@@ -107,59 +107,57 @@ bool failed = use_facet<
107
  The first argument provides an object of the `ostreambuf_iterator<>`
108
  class which is an iterator for class `basic_ostream<>`. It bypasses
109
  `ostream`s and uses `streambuf`s directly. Class `locale` relies on
110
  these types as its interface to iostreams, since for flexibility it has
111
  been abstracted away from direct dependence on `ostream`. The second
112
- parameter is a reference to the base subobject of type `ios_base`. It
113
- provides formatting specifications such as field width, and a locale
114
  from which to obtain other facets. If `failed` is `true` then does
115
  `setstate(badbit)`, which may throw an exception, and returns.
116
 
117
  *Returns:* `*this`.
118
 
119
  ##### `basic_ostream::operator<<` <a id="ostream.inserters">[[ostream.inserters]]</a>
120
 
121
  ``` cpp
122
- basic_ostream<charT,traits>& operator<<
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- (basic_ostream<charT,traits>& (*pf)(basic_ostream<charT,traits>&));
124
  ```
125
 
126
  *Effects:* None. Does not behave as a formatted output function (as
127
  described in  [[ostream.formatted.reqmts]]).
128
 
129
- *Returns:* `pf(*this)`.[^33]
130
 
131
  ``` cpp
132
- basic_ostream<charT,traits>& operator<<
133
- (basic_ios<charT,traits>& (*pf)(basic_ios<charT,traits>&));
134
  ```
135
 
136
  *Effects:* Calls `pf(*this)`. This inserter does not behave as a
137
  formatted output function (as described
138
  in  [[ostream.formatted.reqmts]]).
139
 
140
- *Returns:* `*this`.[^34]
141
 
142
  ``` cpp
143
- basic_ostream<charT,traits>& operator<<
144
- (ios_base& (*pf)(ios_base&));
145
  ```
146
 
147
  *Effects:* Calls `pf(*this)`. This inserter does not behave as a
148
  formatted output function (as described
149
  in  [[ostream.formatted.reqmts]]).
150
 
151
  *Returns:* `*this`.
152
 
153
  ``` cpp
154
- basic_ostream<charT,traits>& operator<<
155
- (basic_streambuf<charT,traits>* sb);
156
  ```
157
 
158
- *Effects:* Behaves as an unformatted output function (as described
159
- in  [[ostream.unformatted]], paragraph 1). After the sentry object is
160
- constructed, if `sb` is null calls `setstate(badbit)` (which may throw
161
  `ios_base::failure`).
162
 
163
  Gets characters from `sb` and inserts them in `*this`. Characters are
164
  read from `sb` and inserted until any of the following occurs:
165
 
@@ -174,55 +172,58 @@ exception was thrown while extracting a character, the function sets
174
  `failbit` in error state, and if `failbit` is on in `exceptions()` the
175
  caught exception is rethrown.
176
 
177
  *Returns:* `*this`.
178
 
 
 
 
 
 
 
 
 
 
 
 
 
179
  ##### Character inserter function templates <a id="ostream.inserters.character">[[ostream.inserters.character]]</a>
180
 
181
  ``` cpp
182
  template<class charT, class traits>
183
- basic_ostream<charT,traits>& operator<<(basic_ostream<charT,traits>& out,
184
- charT c);
185
  template<class charT, class traits>
186
- basic_ostream<charT,traits>& operator<<(basic_ostream<charT,traits>& out,
187
- char c);
188
  // specialization
189
  template<class traits>
190
- basic_ostream<char,traits>& operator<<(basic_ostream<char,traits>& out,
191
- char c);
192
  // signed and unsigned
193
  template<class traits>
194
- basic_ostream<char,traits>& operator<<(basic_ostream<char,traits>& out,
195
- signed char c);
196
  template<class traits>
197
- basic_ostream<char,traits>& operator<<(basic_ostream<char,traits>& out,
198
- unsigned char c);
199
  ```
200
 
201
- *Effects:* Behaves as a formatted output function
202
- (  [[ostream.formatted.reqmts]]) of `out`. Constructs a character
203
- sequence `seq`. If `c` has type `char` and the character type of the
204
- stream is not `char`, then `seq` consists of `out.widen(c)`; otherwise
205
- `seq` consists of `c`. Determines padding for `seq` as described
206
- in  [[ostream.formatted.reqmts]]. Inserts `seq` into `out`. Calls
207
- `os.width(0)`.
208
 
209
  *Returns:* `out`.
210
 
211
  ``` cpp
212
  template<class charT, class traits>
213
- basic_ostream<charT,traits>& operator<<(basic_ostream<charT,traits>& out,
214
- const charT* s);
215
  template<class charT, class traits>
216
- basic_ostream<charT,traits>& operator<<(basic_ostream<charT,traits>& out,
217
- const char* s);
218
  template<class traits>
219
- basic_ostream<char,traits>& operator<<(basic_ostream<char,traits>& out,
220
- const char* s);
221
  template<class traits>
222
- basic_ostream<char,traits>& operator<<(basic_ostream<char,traits>& out,
223
- const signed char* s);
224
  template<class traits>
225
  basic_ostream<char, traits>& operator<<(basic_ostream<char, traits>& out,
226
  const unsigned char* s);
227
  ```
228
 
@@ -237,11 +238,11 @@ would be computed as if by:
237
  - `traits::length(s)` for the overload where the first argument is of
238
  type `basic_ostream<charT, traits>&` and the second is of type
239
  `const charT*`, and also for the overload where the first argument is
240
  of type `basic_ostream<char, traits>&` and the second is of type
241
  `const char*`,
242
- - `std::char_traits<char>::length(s)` for the overload where the first
243
  argument is of type `basic_ostream<charT, traits>&` and the second is
244
  of type `const char*`,
245
  - `traits::length(reinterpret_cast<const char*>(s))` for the other two
246
  overloads.
247
 
 
6
  object of class `sentry`. If this object returns `true` when converted
7
  to a value of type `bool`, the function endeavors to generate the
8
  requested output. If the generation fails, then the formatted output
9
  function does `setstate(ios_base::failbit)`, which might throw an
10
  exception. If an exception is thrown during output, then `ios::badbit`
11
+ is turned on[^33] in `*this`’s error state. If
12
  `(exceptions()&badbit) != 0` then the exception is rethrown. Whether or
13
  not an exception is thrown, the `sentry` object is destroyed before
14
  leaving the formatted output function. If no exception is thrown, the
15
  result of the formatted output function is `*this`.
16
 
 
107
  The first argument provides an object of the `ostreambuf_iterator<>`
108
  class which is an iterator for class `basic_ostream<>`. It bypasses
109
  `ostream`s and uses `streambuf`s directly. Class `locale` relies on
110
  these types as its interface to iostreams, since for flexibility it has
111
  been abstracted away from direct dependence on `ostream`. The second
112
+ parameter is a reference to the base class subobject of type `ios_base`.
113
+ It provides formatting specifications such as field width, and a locale
114
  from which to obtain other facets. If `failed` is `true` then does
115
  `setstate(badbit)`, which may throw an exception, and returns.
116
 
117
  *Returns:* `*this`.
118
 
119
  ##### `basic_ostream::operator<<` <a id="ostream.inserters">[[ostream.inserters]]</a>
120
 
121
  ``` cpp
122
+ basic_ostream<charT, traits>&
123
+ operator<<(basic_ostream<charT, traits>& (*pf)(basic_ostream<charT, traits>&));
124
  ```
125
 
126
  *Effects:* None. Does not behave as a formatted output function (as
127
  described in  [[ostream.formatted.reqmts]]).
128
 
129
+ *Returns:* `pf(*this)`.[^34]
130
 
131
  ``` cpp
132
+ basic_ostream<charT, traits>&
133
+ operator<<(basic_ios<charT, traits>& (*pf)(basic_ios<charT, traits>&));
134
  ```
135
 
136
  *Effects:* Calls `pf(*this)`. This inserter does not behave as a
137
  formatted output function (as described
138
  in  [[ostream.formatted.reqmts]]).
139
 
140
+ *Returns:* `*this`.[^35]
141
 
142
  ``` cpp
143
+ basic_ostream<charT, traits>& operator<<(ios_base& (*pf)(ios_base&));
 
144
  ```
145
 
146
  *Effects:* Calls `pf(*this)`. This inserter does not behave as a
147
  formatted output function (as described
148
  in  [[ostream.formatted.reqmts]]).
149
 
150
  *Returns:* `*this`.
151
 
152
  ``` cpp
153
+ basic_ostream<charT, traits>& operator<<(basic_streambuf<charT, traits>* sb);
 
154
  ```
155
 
156
+ *Effects:* Behaves as an unformatted output function
157
+ ([[ostream.unformatted]]). After the sentry object is constructed, if
158
+ `sb` is null calls `setstate(badbit)` (which may throw
159
  `ios_base::failure`).
160
 
161
  Gets characters from `sb` and inserts them in `*this`. Characters are
162
  read from `sb` and inserted until any of the following occurs:
163
 
 
172
  `failbit` in error state, and if `failbit` is on in `exceptions()` the
173
  caught exception is rethrown.
174
 
175
  *Returns:* `*this`.
176
 
177
+ ``` cpp
178
+ basic_ostream<charT, traits>& operator<<(nullptr_t);
179
+ ```
180
+
181
+ *Effects:* Equivalent to:
182
+
183
+ ``` cpp
184
+ return *this << s;
185
+ ```
186
+
187
+ where `s` is an *implementation-defined* NTCTS ([[defns.ntcts]]).
188
+
189
  ##### Character inserter function templates <a id="ostream.inserters.character">[[ostream.inserters.character]]</a>
190
 
191
  ``` cpp
192
  template<class charT, class traits>
193
+ basic_ostream<charT, traits>& operator<<(basic_ostream<charT, traits>& out, charT c);
 
194
  template<class charT, class traits>
195
+ basic_ostream<charT, traits>& operator<<(basic_ostream<charT, traits>& out, char c);
 
196
  // specialization
197
  template<class traits>
198
+ basic_ostream<char, traits>& operator<<(basic_ostream<char, traits>& out, char c);
 
199
  // signed and unsigned
200
  template<class traits>
201
+ basic_ostream<char, traits>& operator<<(basic_ostream<char, traits>& out, signed char c);
 
202
  template<class traits>
203
+ basic_ostream<char, traits>& operator<<(basic_ostream<char, traits>& out, unsigned char c);
 
204
  ```
205
 
206
+ *Effects:* Behaves as a formatted output
207
+ function ([[ostream.formatted.reqmts]]) of `out`. Constructs a
208
+ character sequence `seq`. If `c` has type `char` and the character type
209
+ of the stream is not `char`, then `seq` consists of `out.widen(c)`;
210
+ otherwise `seq` consists of `c`. Determines padding for `seq` as
211
+ described in  [[ostream.formatted.reqmts]]. Inserts `seq` into `out`.
212
+ Calls `os.width(0)`.
213
 
214
  *Returns:* `out`.
215
 
216
  ``` cpp
217
  template<class charT, class traits>
218
+ basic_ostream<charT, traits>& operator<<(basic_ostream<charT, traits>& out, const charT* s);
 
219
  template<class charT, class traits>
220
+ basic_ostream<charT, traits>& operator<<(basic_ostream<charT, traits>& out, const char* s);
 
221
  template<class traits>
222
+ basic_ostream<char, traits>& operator<<(basic_ostream<char, traits>& out, const char* s);
 
223
  template<class traits>
224
+ basic_ostream<char, traits>& operator<<(basic_ostream<char, traits>& out, const signed char* s);
 
225
  template<class traits>
226
  basic_ostream<char, traits>& operator<<(basic_ostream<char, traits>& out,
227
  const unsigned char* s);
228
  ```
229
 
 
238
  - `traits::length(s)` for the overload where the first argument is of
239
  type `basic_ostream<charT, traits>&` and the second is of type
240
  `const charT*`, and also for the overload where the first argument is
241
  of type `basic_ostream<char, traits>&` and the second is of type
242
  `const char*`,
243
+ - `char_traits<char>::length(s)` for the overload where the first
244
  argument is of type `basic_ostream<charT, traits>&` and the second is
245
  of type `const char*`,
246
  - `traits::length(reinterpret_cast<const char*>(s))` for the other two
247
  overloads.
248