tmp/tmp1_k8wcnv/{from.md → to.md}
RENAMED
|
@@ -5,94 +5,130 @@ unqualified, so as to enable argument dependent lookup
|
|
| 5 |
[[basic.lookup.argdep]]. In the following paragraphs, let `is` denote an
|
| 6 |
object of type `basic_istream<charT, traits>` and let `I` be
|
| 7 |
`basic_istream<charT, traits>&`, where `charT` and `traits` are template
|
| 8 |
parameters in that context.
|
| 9 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 10 |
``` cpp
|
|
|
|
|
|
|
|
|
|
| 11 |
template<class charT, class traits, class Alloc, class Parsable>
|
| 12 |
unspecified
|
| 13 |
parse(const basic_string<charT, traits, Alloc>& fmt, Parsable& tp);
|
| 14 |
```
|
| 15 |
|
|
|
|
|
|
|
|
|
|
| 16 |
*Constraints:* The expression
|
| 17 |
|
| 18 |
``` cpp
|
| 19 |
-
from_stream(declval<basic_istream<charT, traits>&>(),
|
| 20 |
```
|
| 21 |
|
| 22 |
-
is well-formed when treated as an unevaluated
|
|
|
|
| 23 |
|
| 24 |
*Returns:* A manipulator such that the expression `is >> parse(fmt, tp)`
|
| 25 |
-
has type `I`, has value `is`, and calls
|
| 26 |
-
`from_stream(is, fmt.c_str(), tp)`.
|
| 27 |
|
| 28 |
``` cpp
|
|
|
|
|
|
|
|
|
|
|
|
|
| 29 |
template<class charT, class traits, class Alloc, class Parsable>
|
| 30 |
unspecified
|
| 31 |
parse(const basic_string<charT, traits, Alloc>& fmt, Parsable& tp,
|
| 32 |
basic_string<charT, traits, Alloc>& abbrev);
|
| 33 |
```
|
| 34 |
|
|
|
|
|
|
|
|
|
|
| 35 |
*Constraints:* The expression
|
| 36 |
|
| 37 |
``` cpp
|
| 38 |
-
from_stream(declval<basic_istream<charT, traits>&>(),
|
| 39 |
```
|
| 40 |
|
| 41 |
-
is well-formed when treated as an unevaluated
|
|
|
|
| 42 |
|
| 43 |
*Returns:* A manipulator such that the expression
|
| 44 |
`is >> parse(fmt, tp, abbrev)` has type `I`, has value `is`, and calls
|
| 45 |
-
`from_stream(is,
|
| 46 |
|
| 47 |
``` cpp
|
|
|
|
|
|
|
|
|
|
| 48 |
template<class charT, class traits, class Alloc, class Parsable>
|
| 49 |
unspecified
|
| 50 |
parse(const basic_string<charT, traits, Alloc>& fmt, Parsable& tp,
|
| 51 |
minutes& offset);
|
| 52 |
```
|
| 53 |
|
|
|
|
|
|
|
|
|
|
|
|
|
| 54 |
*Constraints:* The expression
|
| 55 |
|
| 56 |
``` cpp
|
| 57 |
from_stream(declval<basic_istream<charT, traits>&>(),
|
| 58 |
-
|
| 59 |
declval<basic_string<charT, traits, Alloc>*>(),
|
| 60 |
&offset)
|
| 61 |
```
|
| 62 |
|
| 63 |
-
is well-formed when treated as an unevaluated
|
|
|
|
| 64 |
|
| 65 |
*Returns:* A manipulator such that the expression
|
| 66 |
`is >> parse(fmt, tp, offset)` has type `I`, has value `is`, and calls:
|
| 67 |
|
| 68 |
``` cpp
|
| 69 |
from_stream(is,
|
| 70 |
-
|
| 71 |
static_cast<basic_string<charT, traits, Alloc>*>(nullptr),
|
| 72 |
&offset)
|
| 73 |
```
|
| 74 |
|
| 75 |
``` cpp
|
|
|
|
|
|
|
|
|
|
|
|
|
| 76 |
template<class charT, class traits, class Alloc, class Parsable>
|
| 77 |
unspecified
|
| 78 |
parse(const basic_string<charT, traits, Alloc>& fmt, Parsable& tp,
|
| 79 |
basic_string<charT, traits, Alloc>& abbrev, minutes& offset);
|
| 80 |
```
|
| 81 |
|
|
|
|
|
|
|
|
|
|
| 82 |
*Constraints:* The expression
|
| 83 |
|
| 84 |
``` cpp
|
| 85 |
from_stream(declval<basic_istream<charT, traits>&>(),
|
| 86 |
-
|
| 87 |
```
|
| 88 |
|
| 89 |
-
is well-formed when treated as an unevaluated
|
|
|
|
| 90 |
|
| 91 |
*Returns:* A manipulator such that the expression
|
| 92 |
`is >> parse(fmt, tp, abbrev, offset)` has type `I`, has value `is`, and
|
| 93 |
-
calls `from_stream(is,
|
| 94 |
|
| 95 |
All `from_stream` overloads behave as unformatted input functions,
|
| 96 |
except that they have an unspecified effect on the value returned by
|
| 97 |
subsequent calls to `basic_istream<>::gcount()`. Each overload takes a
|
| 98 |
format string containing ordinary characters and flags which have
|
|
@@ -101,29 +137,66 @@ by `E` or `O`. During parsing each flag interprets characters as parts
|
|
| 101 |
of date and time types according to [[time.parse.spec]]. Some flags can
|
| 102 |
be modified by a width parameter given as a positive decimal integer
|
| 103 |
called out as `N` below which governs how many characters are parsed
|
| 104 |
from the stream in interpreting the flag. All characters in the format
|
| 105 |
string that are not represented in [[time.parse.spec]], except for
|
| 106 |
-
|
| 107 |
-
|
| 108 |
-
stream.
|
| 109 |
|
| 110 |
If the type being parsed cannot represent the information that the
|
| 111 |
format flag refers to, `is.setstate(ios_base::failbit)` is called.
|
| 112 |
|
| 113 |
[*Example 1*: A `duration` cannot represent a
|
| 114 |
`weekday`. — *end example*]
|
| 115 |
|
| 116 |
-
However, if a flag refers to a “time of day” (e.g. `%H`, `%I`, `%p`,
|
| 117 |
etc.), then a specialization of `duration` is parsed as the time of day
|
| 118 |
elapsed since midnight.
|
| 119 |
|
| 120 |
If the `from_stream` overload fails to parse everything specified by the
|
| 121 |
format string, or if insufficient information is parsed to specify a
|
| 122 |
complete duration, time point, or calendrical data structure,
|
| 123 |
`setstate(ios_base::failbit)` is called on the `basic_istream`.
|
| 124 |
|
| 125 |
-
|
| 126 |
-
|
| 127 |
-
|
| 128 |
-
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 129 |
|
|
|
|
| 5 |
[[basic.lookup.argdep]]. In the following paragraphs, let `is` denote an
|
| 6 |
object of type `basic_istream<charT, traits>` and let `I` be
|
| 7 |
`basic_istream<charT, traits>&`, where `charT` and `traits` are template
|
| 8 |
parameters in that context.
|
| 9 |
|
| 10 |
+
*Recommended practice:* Implementations should make it difficult to
|
| 11 |
+
accidentally store or use a manipulator that may contain a dangling
|
| 12 |
+
reference to a format string, for example by making the manipulators
|
| 13 |
+
produced by `parse` immovable and preventing stream extraction into an
|
| 14 |
+
lvalue of such a manipulator type.
|
| 15 |
+
|
| 16 |
``` cpp
|
| 17 |
+
template<class charT, class Parsable>
|
| 18 |
+
unspecified
|
| 19 |
+
parse(const charT* fmt, Parsable& tp);
|
| 20 |
template<class charT, class traits, class Alloc, class Parsable>
|
| 21 |
unspecified
|
| 22 |
parse(const basic_string<charT, traits, Alloc>& fmt, Parsable& tp);
|
| 23 |
```
|
| 24 |
|
| 25 |
+
Let F be `fmt` for the first overload and `fmt.c_str()` for the second
|
| 26 |
+
overload. Let `traits` be `char_traits<charT>` for the first overload.
|
| 27 |
+
|
| 28 |
*Constraints:* The expression
|
| 29 |
|
| 30 |
``` cpp
|
| 31 |
+
from_stream(declval<basic_istream<charT, traits>&>(), F, tp)
|
| 32 |
```
|
| 33 |
|
| 34 |
+
is well-formed when treated as an unevaluated
|
| 35 |
+
operand [[term.unevaluated.operand]].
|
| 36 |
|
| 37 |
*Returns:* A manipulator such that the expression `is >> parse(fmt, tp)`
|
| 38 |
+
has type `I`, has value `is`, and calls `from_stream(is, `F`, tp)`.
|
|
|
|
| 39 |
|
| 40 |
``` cpp
|
| 41 |
+
template<class charT, class traits, class Alloc, class Parsable>
|
| 42 |
+
unspecified
|
| 43 |
+
parse(const charT* fmt, Parsable& tp,
|
| 44 |
+
basic_string<charT, traits, Alloc>& abbrev);
|
| 45 |
template<class charT, class traits, class Alloc, class Parsable>
|
| 46 |
unspecified
|
| 47 |
parse(const basic_string<charT, traits, Alloc>& fmt, Parsable& tp,
|
| 48 |
basic_string<charT, traits, Alloc>& abbrev);
|
| 49 |
```
|
| 50 |
|
| 51 |
+
Let F be `fmt` for the first overload and `fmt.c_str()` for the second
|
| 52 |
+
overload.
|
| 53 |
+
|
| 54 |
*Constraints:* The expression
|
| 55 |
|
| 56 |
``` cpp
|
| 57 |
+
from_stream(declval<basic_istream<charT, traits>&>(), F, tp, addressof(abbrev))
|
| 58 |
```
|
| 59 |
|
| 60 |
+
is well-formed when treated as an unevaluated
|
| 61 |
+
operand [[term.unevaluated.operand]].
|
| 62 |
|
| 63 |
*Returns:* A manipulator such that the expression
|
| 64 |
`is >> parse(fmt, tp, abbrev)` has type `I`, has value `is`, and calls
|
| 65 |
+
`from_stream(is, `F`, tp, addressof(abbrev))`.
|
| 66 |
|
| 67 |
``` cpp
|
| 68 |
+
template<class charT, class Parsable>
|
| 69 |
+
unspecified
|
| 70 |
+
parse(const charT* fmt, Parsable& tp, minutes& offset);
|
| 71 |
template<class charT, class traits, class Alloc, class Parsable>
|
| 72 |
unspecified
|
| 73 |
parse(const basic_string<charT, traits, Alloc>& fmt, Parsable& tp,
|
| 74 |
minutes& offset);
|
| 75 |
```
|
| 76 |
|
| 77 |
+
Let F be `fmt` for the first overload and `fmt.c_str()` for the second
|
| 78 |
+
overload. Let `traits` be `char_traits<charT>` and `Alloc` be
|
| 79 |
+
`allocator<charT>` for the first overload.
|
| 80 |
+
|
| 81 |
*Constraints:* The expression
|
| 82 |
|
| 83 |
``` cpp
|
| 84 |
from_stream(declval<basic_istream<charT, traits>&>(),
|
| 85 |
+
F, tp,
|
| 86 |
declval<basic_string<charT, traits, Alloc>*>(),
|
| 87 |
&offset)
|
| 88 |
```
|
| 89 |
|
| 90 |
+
is well-formed when treated as an unevaluated
|
| 91 |
+
operand [[term.unevaluated.operand]].
|
| 92 |
|
| 93 |
*Returns:* A manipulator such that the expression
|
| 94 |
`is >> parse(fmt, tp, offset)` has type `I`, has value `is`, and calls:
|
| 95 |
|
| 96 |
``` cpp
|
| 97 |
from_stream(is,
|
| 98 |
+
F, tp,
|
| 99 |
static_cast<basic_string<charT, traits, Alloc>*>(nullptr),
|
| 100 |
&offset)
|
| 101 |
```
|
| 102 |
|
| 103 |
``` cpp
|
| 104 |
+
template<class charT, class traits, class Alloc, class Parsable>
|
| 105 |
+
unspecified
|
| 106 |
+
parse(const charT* fmt, Parsable& tp,
|
| 107 |
+
basic_string<charT, traits, Alloc>& abbrev, minutes& offset);
|
| 108 |
template<class charT, class traits, class Alloc, class Parsable>
|
| 109 |
unspecified
|
| 110 |
parse(const basic_string<charT, traits, Alloc>& fmt, Parsable& tp,
|
| 111 |
basic_string<charT, traits, Alloc>& abbrev, minutes& offset);
|
| 112 |
```
|
| 113 |
|
| 114 |
+
Let F be `fmt` for the first overload and `fmt.c_str()` for the second
|
| 115 |
+
overload.
|
| 116 |
+
|
| 117 |
*Constraints:* The expression
|
| 118 |
|
| 119 |
``` cpp
|
| 120 |
from_stream(declval<basic_istream<charT, traits>&>(),
|
| 121 |
+
F, tp, addressof(abbrev), &offset)
|
| 122 |
```
|
| 123 |
|
| 124 |
+
is well-formed when treated as an unevaluated
|
| 125 |
+
operand [[term.unevaluated.operand]].
|
| 126 |
|
| 127 |
*Returns:* A manipulator such that the expression
|
| 128 |
`is >> parse(fmt, tp, abbrev, offset)` has type `I`, has value `is`, and
|
| 129 |
+
calls `from_stream(is, `F`, tp, addressof(abbrev), &offset)`.
|
| 130 |
|
| 131 |
All `from_stream` overloads behave as unformatted input functions,
|
| 132 |
except that they have an unspecified effect on the value returned by
|
| 133 |
subsequent calls to `basic_istream<>::gcount()`. Each overload takes a
|
| 134 |
format string containing ordinary characters and flags which have
|
|
|
|
| 137 |
of date and time types according to [[time.parse.spec]]. Some flags can
|
| 138 |
be modified by a width parameter given as a positive decimal integer
|
| 139 |
called out as `N` below which governs how many characters are parsed
|
| 140 |
from the stream in interpreting the flag. All characters in the format
|
| 141 |
string that are not represented in [[time.parse.spec]], except for
|
| 142 |
+
whitespace, are parsed unchanged from the stream. A whitespace character
|
| 143 |
+
matches zero or more whitespace characters in the input stream.
|
|
|
|
| 144 |
|
| 145 |
If the type being parsed cannot represent the information that the
|
| 146 |
format flag refers to, `is.setstate(ios_base::failbit)` is called.
|
| 147 |
|
| 148 |
[*Example 1*: A `duration` cannot represent a
|
| 149 |
`weekday`. — *end example*]
|
| 150 |
|
| 151 |
+
However, if a flag refers to a “time of day” (e.g., `%H`, `%I`, `%p`,
|
| 152 |
etc.), then a specialization of `duration` is parsed as the time of day
|
| 153 |
elapsed since midnight.
|
| 154 |
|
| 155 |
If the `from_stream` overload fails to parse everything specified by the
|
| 156 |
format string, or if insufficient information is parsed to specify a
|
| 157 |
complete duration, time point, or calendrical data structure,
|
| 158 |
`setstate(ios_base::failbit)` is called on the `basic_istream`.
|
| 159 |
|
| 160 |
+
**Table: Meaning of `parse` flags** <a id="time.parse.spec">[time.parse.spec]</a>
|
| 161 |
+
|
| 162 |
+
| Flag | Parsed value |
|
| 163 |
+
| ---- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
|
| 164 |
+
| `%a` | The locale's full or abbreviated case-insensitive weekday name. |
|
| 165 |
+
| `%A` | Equivalent to `%a`. |
|
| 166 |
+
| `%b` | The locale's full or abbreviated case-insensitive month name. |
|
| 167 |
+
| `%B` | Equivalent to `%b`. |
|
| 168 |
+
| `%c` | The locale's date and time representation. The modified command `%Ec` interprets the locale's alternate date and time representation. |
|
| 169 |
+
| `%C` | The century as a decimal number. The modified command `%*N*C` specifies the maximum number of characters to read. If `*N*` is not specified, the default is 2. Leading zeroes are permitted but not required. The modified command `%EC` interprets the locale's alternative representation of the century. |
|
| 170 |
+
| `%d` | The day of the month as a decimal number. The modified command `%*N*d` specifies the maximum number of characters to read. If `*N*` is not specified, the default is 2. Leading zeroes are permitted but not required. The modified command `%Od` interprets the locale's alternative representation of the day of the month. |
|
| 171 |
+
| `%D` | Equivalent to `%m/%d/%y`. |
|
| 172 |
+
| `%e` | Equivalent to `%d` and can be modified like `%d`. |
|
| 173 |
+
| `%F` | Equivalent to `%Y-%m-%d`. If modified with a width `*N*`, the width is applied to only `%Y`. |
|
| 174 |
+
| `%g` | The last two decimal digits of the ISO week-based year. The modified command `%*N*g` specifies the maximum number of characters to read. If `*N*` is not specified, the default is 2. Leading zeroes are permitted but not required. |
|
| 175 |
+
| `%G` | The ISO week-based year as a decimal number. The modified command `%*N*G` specifies the maximum number of characters to read. If `*N*` is not specified, the default is 4. Leading zeroes are permitted but not required. |
|
| 176 |
+
| `%h` | Equivalent to `%b`. |
|
| 177 |
+
| `%H` | The hour (24-hour clock) as a decimal number. The modified command `%*N*H` specifies the maximum number of characters to read. If `*N*` is not specified, the default is 2. Leading zeroes are permitted but not required. The modified command `%OH` interprets the locale's alternative representation. |
|
| 178 |
+
| `%I` | The hour (12-hour clock) as a decimal number. The modified command `%*N*I` specifies the maximum number of characters to read. If `*N*` is not specified, the default is 2. Leading zeroes are permitted but not required. The modified command `%OI` interprets the locale's alternative representation. |
|
| 179 |
+
| `%j` | If the type being parsed is a specialization of `duration`, a decimal number of `days`. Otherwise, the day of the year as a decimal number. Jan 1 is `1`. In either case, the modified command `%*N*j` specifies the maximum number of characters to read. If `*N*` is not specified, the default is 3. Leading zeroes are permitted but not required. |
|
| 180 |
+
| `%m` | The month as a decimal number. Jan is `1`. The modified command `%*N*m` specifies the maximum number of characters to read. If `*N*` is not specified, the default is 2. Leading zeroes are permitted but not required. The modified command `%Om` interprets the locale's alternative representation. |
|
| 181 |
+
| `%M` | The minutes as a decimal number. The modified command `%*N*M` specifies the maximum number of characters to read. If `*N*` is not specified, the default is 2. Leading zeroes are permitted but not required. The modified command `%OM` interprets the locale's alternative representation. |
|
| 182 |
+
| `%n` | Matches one whitespace character. *`%n`, `%t`, and a space can be combined to match a wide range of whitespace patterns. For example, `"%n "` matches one or more whitespace characters, and `"%n%t%t"` matches one to three whitespace characters.* |
|
| 183 |
+
| `%p` | The locale's equivalent of the AM/PM designations associated with a 12-hour clock. |
|
| 184 |
+
| `%r` | The locale's 12-hour clock time. |
|
| 185 |
+
| `%R` | Equivalent to `%H:%M`. |
|
| 186 |
+
| `%S` | The seconds as a decimal number. The modified command `%*N*S` specifies the maximum number of characters to read. If `*N*` is not specified, the default is 2 if the input time has a precision convertible to seconds. Otherwise the default width is determined by the decimal precision of the input and the field is interpreted as a `long double` in a fixed format. If encountered, the locale determines the decimal point character. Leading zeroes are permitted but not required. The modified command `%OS` interprets the locale's alternative representation. |
|
| 187 |
+
| `%t` | Matches zero or one whitespace characters. |
|
| 188 |
+
| `%T` | Equivalent to `%H:%M:%S`. |
|
| 189 |
+
| `%u` | The ISO weekday as a decimal number (`1`-`7`), where Monday is `1`. The modified command `%*N*u` specifies the maximum number of characters to read. If `*N*` is not specified, the default is `1`. Leading zeroes are permitted but not required. |
|
| 190 |
+
| `%U` | The week number of the year as a decimal number. The first Sunday of the year is the first day of week `01`. Days of the same year prior to that are in week `00`. The modified command `%*N*U` specifies the maximum number of characters to read. If `*N*` is not specified, the default is 2. Leading zeroes are permitted but not required. The modified command `%OU` interprets the locale's alternative representation. |
|
| 191 |
+
| `%V` | The ISO week-based week number as a decimal number. The modified command `%*N*V` specifies the maximum number of characters to read. If `*N*` is not specified, the default is 2. Leading zeroes are permitted but not required. |
|
| 192 |
+
| `%w` | The weekday as a decimal number (`0`-`6`), where Sunday is `0`. The modified command `%*N*w` specifies the maximum number of characters to read. If `*N*` is not specified, the default is `1`. Leading zeroes are permitted but not required. The modified command `%Ow` interprets the locale's alternative representation. |
|
| 193 |
+
| `%W` | The week number of the year as a decimal number. The first Monday of the year is the first day of week `01`. Days of the same year prior to that are in week `00`. The modified command `%*N*W` specifies the maximum number of characters to read. If `*N*` is not specified, the default is 2. Leading zeroes are permitted but not required. The modified command `%OW` interprets the locale's alternative representation. |
|
| 194 |
+
| `%x` | The locale's date representation. The modified command `%Ex` interprets the locale's alternate date representation. |
|
| 195 |
+
| `%X` | The locale's time representation. The modified command `%EX` interprets the locale's alternate time representation. |
|
| 196 |
+
| `%y` | The last two decimal digits of the year. If the century is not otherwise specified (e.g., with `%C`), values in the range {[}`69`, `99`{]} are presumed to refer to the years 1969 to 1999, and values in the range {[}`00`, `68`{]} are presumed to refer to the years 2000 to 2068. The modified command `%*N*y` specifies the maximum number of characters to read. If `*N*` is not specified, the default is 2. Leading zeroes are permitted but not required. The modified commands `%Ey` and `%Oy` interpret the locale's alternative representation. |
|
| 197 |
+
| `%Y` | The year as a decimal number. The modified command `%*N*Y` specifies the maximum number of characters to read. If `*N*` is not specified, the default is 4. Leading zeroes are permitted but not required. The modified command `%EY` interprets the locale's alternative representation. |
|
| 198 |
+
| `%z` | The offset from UTC in the format `[+|-]hh[mm]`. For example `-0430` refers to 4 hours 30 minutes behind UTC, and `04` refers to 4 hours ahead of UTC. The modified commands `%Ez` and `%Oz` parse a `:` between the hours and minutes and render leading zeroes on the hour field optional: `[+|-]h[h][:mm]`. For example `-04:30` refers to 4 hours 30 minutes behind UTC, and `4` refers to 4 hours ahead of UTC. |
|
| 199 |
+
| `%Z` | The time zone abbreviation or name. A single word is parsed. This word can only contain characters from the basic character set [[lex.charset]] that are alphanumeric, or one of `'_'`, `'/'`, `'-'`, or `'+'`. |
|
| 200 |
+
| `%%` | A `%` character is extracted. |
|
| 201 |
+
|
| 202 |
|