From Jason Turner

[locale.time.get]

C++20 → C++23 8.4 KB 91 lines
Current Draft | LaTeX Source
Archived: C++20 | C++23
Markdown: C++20 | C++23
Explore in Adventure Game

Diff to HTML by rtfpessoa

Files changed (1) hide show
  1. tmp/tmpft94s67z/{from.md → to.md} +42 -41
tmp/tmpft94s67z/{from.md → to.md} RENAMED
@@ -1,7 +1,9 @@
1
  #### Class template `time_get` <a id="locale.time.get">[[locale.time.get]]</a>
2
 
 
 
3
  ``` cpp
4
  namespace std {
5
  class time_base {
6
  public:
7
  enum dateorder { no_order, dmy, mdy, ymd, ydm };
@@ -51,19 +53,17 @@ namespace std {
51
  ios_base::iostate& err, tm* t, char format, char modifier) const;
52
  };
53
  }
54
  ```
55
 
56
- `time_get`
57
-
58
- is used to parse a character sequence, extracting components of a time
59
- or date into a `struct tm` object. Each `get` member parses a format as
60
- produced by a corresponding format specifier to `time_put<>::put`. If
61
  the sequence being parsed matches the correct format, the corresponding
62
- members of the `struct tm` argument are set to the values used to
63
- produce the sequence; otherwise either an error is reported or
64
- unspecified values are assigned.[^15]
65
 
66
  If the end iterator is reached during parsing by any of the `get()`
67
  member functions, the member sets `ios_base::eofbit` in `err`.
68
 
69
  ##### Members <a id="locale.time.get.members">[[locale.time.get.members]]</a>
@@ -129,12 +129,12 @@ the first of the following conditions holds:
129
  - The expression `s == end` evaluates to `true`, in which case the
130
  function evaluates `err = ios_base::eofbit | ios_base::failbit`.
131
  - The next element of `fmt` is equal to `’%’`, optionally followed by a
132
  modifier character, followed by a conversion specifier character,
133
  `format`, together forming a conversion specification valid for the
134
- ISO/IEC 9945 function `strptime`. If the number of elements in the
135
- range \[`fmt`, `fmtend`) is not sufficient to unambiguously determine
136
  whether the conversion specification is complete and valid, the
137
  function evaluates `err = ios_base::failbit`. Otherwise, the function
138
  evaluates `s = do_get(s, end, f, err, t, format, modifier)`, where the
139
  value of `modifier` is `’\0’` when the optional modifier is absent
140
  from the conversion specification. If `err == ios_base::goodbit` holds
@@ -165,37 +165,38 @@ so. — *end note*]
165
  dateorder do_date_order() const;
166
  ```
167
 
168
  *Returns:* An enumeration value indicating the preferred order of
169
  components for those date formats that are composed of day, month, and
170
- year.[^16] Returns `no_order` if the date format specified by `’x’`
171
- contains other variable components (e.g., Julian day, week number, week
172
- day).
 
173
 
174
  ``` cpp
175
  iter_type do_get_time(iter_type s, iter_type end, ios_base& str,
176
  ios_base::iostate& err, tm* t) const;
177
  ```
178
 
179
  *Effects:* Reads characters starting at `s` until it has extracted those
180
- `struct tm` members, and remaining format characters, used by
181
- `time_put<>::put` to produce the format specified by `"%H:%M:%S"`, or
182
- until it encounters an error or end of sequence.
183
 
184
  *Returns:* An iterator pointing immediately beyond the last character
185
  recognized as possibly part of a valid time.
186
 
187
  ``` cpp
188
  iter_type do_get_date(iter_type s, iter_type end, ios_base& str,
189
  ios_base::iostate& err, tm* t) const;
190
  ```
191
 
192
  *Effects:* Reads characters starting at `s` until it has extracted those
193
- `struct tm` members and remaining format characters used by
194
- `time_put<>::put` to produce one of the following formats, or until it
195
- encounters an error. The format depends on the value returned by
196
- `date_order()` as shown in [[locale.time.get.dogetdate]].
197
 
198
  **Table: `do_get_date` effects** <a id="locale.time.get.dogetdate">[locale.time.get.dogetdate]</a>
199
 
200
  | `date_order()` | Format |
201
  | -------------- | ---------- |
@@ -219,13 +220,13 @@ iter_type do_get_monthname(iter_type s, iter_type end, ios_base& str,
219
  ios_base::iostate& err, tm* t) const;
220
  ```
221
 
222
  *Effects:* Reads characters starting at `s` until it has extracted the
223
  (perhaps abbreviated) name of a weekday or month. If it finds an
224
- abbreviation that is followed by characters that could match a full
225
- name, it continues reading until it matches the full name or fails. It
226
- sets the appropriate `struct tm` member accordingly.
227
 
228
  *Returns:* An iterator pointing immediately beyond the last character
229
  recognized as part of a valid name.
230
 
231
  ``` cpp
@@ -248,31 +249,31 @@ iter_type do_get(iter_type s, iter_type end, ios_base& f,
248
 
249
  *Preconditions:* `t` points to an object.
250
 
251
  *Effects:* The function starts by evaluating `err = ios_base::goodbit`.
252
  It then reads characters starting at `s` until it encounters an error,
253
- or until it has extracted and assigned those `struct tm` members, and
254
- any remaining format characters, corresponding to a conversion directive
255
- appropriate for the ISO/IEC 9945 function `strptime`, formed by
256
- concatenating `’%’`, the `modifier` character, when non-NUL, and the
257
- `format` character. When the concatenation fails to yield a complete
258
- valid directive the function leaves the object pointed to by `t`
259
- unchanged and evaluates `err |= ios_base::failbit`. When `s == end`
260
- evaluates to `true` after reading a character the function evaluates
261
  `err |= ios_base::eofbit`.
262
 
263
- For complex conversion directives such as `%c`, `%x`, or `%X`, or
264
- directives that involve the optional modifiers `E` or `O`, when the
265
- function is unable to unambiguously determine some or all `struct tm`
266
- members from the input sequence \[`s`, `end`), it evaluates
267
- `err |= ios_base::eofbit`. In such cases the values of those `struct tm`
268
  members are unspecified and may be outside their valid range.
269
 
270
- *Remarks:* It is unspecified whether multiple calls to `do_get()` with
271
- the address of the same `struct tm` object will update the current
272
- contents of the object or simply overwrite its members. Portable
273
- programs should zero out the object before invoking the function.
274
-
275
  *Returns:* An iterator pointing immediately beyond the last character
276
  recognized as possibly part of a valid input sequence for the given
277
  `format` and `modifier`.
278
 
 
 
 
 
 
 
1
  #### Class template `time_get` <a id="locale.time.get">[[locale.time.get]]</a>
2
 
3
+ ##### General <a id="locale.time.get.general">[[locale.time.get.general]]</a>
4
+
5
  ``` cpp
6
  namespace std {
7
  class time_base {
8
  public:
9
  enum dateorder { no_order, dmy, mdy, ymd, ydm };
 
53
  ios_base::iostate& err, tm* t, char format, char modifier) const;
54
  };
55
  }
56
  ```
57
 
58
+ `time_get` is used to parse a character sequence, extracting components
59
+ of a time or date into a `tm` object. Each `get` member parses a format
60
+ as produced by a corresponding format specifier to `time_put<>::put`. If
 
 
61
  the sequence being parsed matches the correct format, the corresponding
62
+ members of the `tm` argument are set to the values used to produce the
63
+ sequence; otherwise either an error is reported or unspecified values
64
+ are assigned.[^15]
65
 
66
  If the end iterator is reached during parsing by any of the `get()`
67
  member functions, the member sets `ios_base::eofbit` in `err`.
68
 
69
  ##### Members <a id="locale.time.get.members">[[locale.time.get.members]]</a>
 
129
  - The expression `s == end` evaluates to `true`, in which case the
130
  function evaluates `err = ios_base::eofbit | ios_base::failbit`.
131
  - The next element of `fmt` is equal to `’%’`, optionally followed by a
132
  modifier character, followed by a conversion specifier character,
133
  `format`, together forming a conversion specification valid for the
134
+ POSIX function `strptime`. If the number of elements in the range
135
+ \[`fmt`, `fmtend`) is not sufficient to unambiguously determine
136
  whether the conversion specification is complete and valid, the
137
  function evaluates `err = ios_base::failbit`. Otherwise, the function
138
  evaluates `s = do_get(s, end, f, err, t, format, modifier)`, where the
139
  value of `modifier` is `’\0’` when the optional modifier is absent
140
  from the conversion specification. If `err == ios_base::goodbit` holds
 
165
  dateorder do_date_order() const;
166
  ```
167
 
168
  *Returns:* An enumeration value indicating the preferred order of
169
  components for those date formats that are composed of day, month, and
170
+ year.[^16]
171
+
172
+ Returns `no_order` if the date format specified by `’x’` contains other
173
+ variable components (e.g., Julian day, week number, week day).
174
 
175
  ``` cpp
176
  iter_type do_get_time(iter_type s, iter_type end, ios_base& str,
177
  ios_base::iostate& err, tm* t) const;
178
  ```
179
 
180
  *Effects:* Reads characters starting at `s` until it has extracted those
181
+ `tm` members, and remaining format characters, used by `time_put<>::put`
182
+ to produce the format specified by `"%H:%M:%S"`, or until it encounters
183
+ an error or end of sequence.
184
 
185
  *Returns:* An iterator pointing immediately beyond the last character
186
  recognized as possibly part of a valid time.
187
 
188
  ``` cpp
189
  iter_type do_get_date(iter_type s, iter_type end, ios_base& str,
190
  ios_base::iostate& err, tm* t) const;
191
  ```
192
 
193
  *Effects:* Reads characters starting at `s` until it has extracted those
194
+ `tm` members and remaining format characters used by `time_put<>::put`
195
+ to produce one of the following formats, or until it encounters an
196
+ error. The format depends on the value returned by `date_order()` as
197
+ shown in [[locale.time.get.dogetdate]].
198
 
199
  **Table: `do_get_date` effects** <a id="locale.time.get.dogetdate">[locale.time.get.dogetdate]</a>
200
 
201
  | `date_order()` | Format |
202
  | -------------- | ---------- |
 
220
  ios_base::iostate& err, tm* t) const;
221
  ```
222
 
223
  *Effects:* Reads characters starting at `s` until it has extracted the
224
  (perhaps abbreviated) name of a weekday or month. If it finds an
225
+ abbreviation that is followed by characters that can match a full name,
226
+ it continues reading until it matches the full name or fails. It sets
227
+ the appropriate `tm` member accordingly.
228
 
229
  *Returns:* An iterator pointing immediately beyond the last character
230
  recognized as part of a valid name.
231
 
232
  ``` cpp
 
249
 
250
  *Preconditions:* `t` points to an object.
251
 
252
  *Effects:* The function starts by evaluating `err = ios_base::goodbit`.
253
  It then reads characters starting at `s` until it encounters an error,
254
+ or until it has extracted and assigned those `tm` members, and any
255
+ remaining format characters, corresponding to a conversion specification
256
+ appropriate for the POSIX function `strptime`, formed by concatenating
257
+ `’%’`, the `modifier` character, when non-NUL, and the `format`
258
+ character. When the concatenation fails to yield a complete valid
259
+ directive the function leaves the object pointed to by `t` unchanged and
260
+ evaluates `err |= ios_base::failbit`. When `s == end` evaluates to
261
+ `true` after reading a character the function evaluates
262
  `err |= ios_base::eofbit`.
263
 
264
+ For complex conversion specifications such as `%c`, `%x`, or `%X`, or
265
+ conversion specifications that involve the optional modifiers `E` or
266
+ `O`, when the function is unable to unambiguously determine some or all
267
+ `tm` members from the input sequence \[`s`, `end`), it evaluates
268
+ `err |= ios_base::eofbit`. In such cases the values of those `tm`
269
  members are unspecified and may be outside their valid range.
270
 
 
 
 
 
 
271
  *Returns:* An iterator pointing immediately beyond the last character
272
  recognized as possibly part of a valid input sequence for the given
273
  `format` and `modifier`.
274
 
275
+ *Remarks:* It is unspecified whether multiple calls to `do_get()` with
276
+ the address of the same `tm` object will update the current contents of
277
+ the object or simply overwrite its members. Portable programs should
278
+ zero out the object before invoking the function.
279
+