tmp/tmp8vp47q5c/{from.md → to.md}
RENAMED
|
@@ -0,0 +1,90 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 1 |
+
### Primitive numeric output conversion <a id="utility.to.chars">[[utility.to.chars]]</a>
|
| 2 |
+
|
| 3 |
+
All functions named `to_chars` convert `value` into a character string
|
| 4 |
+
by successively filling the range \[`first`, `last`), where \[`first`,
|
| 5 |
+
`last`) is required to be a valid range. If the member `ec` of the
|
| 6 |
+
return value is such that the value, when converted to `bool`, is
|
| 7 |
+
`false`, the conversion was successful and the member `ptr` is the
|
| 8 |
+
one-past-the-end pointer of the characters written. Otherwise, the
|
| 9 |
+
member `ec` has the value `errc::value_too_large`, the member `ptr` has
|
| 10 |
+
the value `last`, and the contents of the range \[`first`, `last`) are
|
| 11 |
+
unspecified.
|
| 12 |
+
|
| 13 |
+
The functions that take a floating-point `value` but not a `precision`
|
| 14 |
+
parameter ensure that the string representation consists of the smallest
|
| 15 |
+
number of characters such that there is at least one digit before the
|
| 16 |
+
radix point (if present) and parsing the representation using the
|
| 17 |
+
corresponding `from_chars` function recovers `value` exactly.
|
| 18 |
+
|
| 19 |
+
[*Note 1*: This guarantee applies only if `to_chars` and `from_chars`
|
| 20 |
+
are executed on the same implementation. — *end note*]
|
| 21 |
+
|
| 22 |
+
The functions taking a `chars_format` parameter determine the conversion
|
| 23 |
+
specifier for `printf` as follows: The conversion specifier is `f` if
|
| 24 |
+
`fmt` is `chars_format::fixed`, `e` if `fmt` is
|
| 25 |
+
`chars_format::scientific`, `a` (without leading `"0x"` in the result)
|
| 26 |
+
if `fmt` is `chars_format::hex`, and `g` if `fmt` is
|
| 27 |
+
`chars_format::general`.
|
| 28 |
+
|
| 29 |
+
``` cpp
|
| 30 |
+
to_chars_result to_chars(char* first, char* last, see below value, int base = 10);
|
| 31 |
+
```
|
| 32 |
+
|
| 33 |
+
*Requires:* `base` has a value between 2 and 36 (inclusive).
|
| 34 |
+
|
| 35 |
+
*Effects:* The value of `value` is converted to a string of digits in
|
| 36 |
+
the given base (with no redundant leading zeroes). Digits in the range
|
| 37 |
+
10..35 (inclusive) are represented as lowercase characters `a`..`z`. If
|
| 38 |
+
`value` is less than zero, the representation starts with a minus sign.
|
| 39 |
+
|
| 40 |
+
*Throws:* Nothing.
|
| 41 |
+
|
| 42 |
+
*Remarks:* The implementation shall provide overloads for all signed and
|
| 43 |
+
unsigned integer types and `char` as the type of the parameter `value`.
|
| 44 |
+
|
| 45 |
+
``` cpp
|
| 46 |
+
to_chars_result to_chars(char* first, char* last, float value);
|
| 47 |
+
to_chars_result to_chars(char* first, char* last, double value);
|
| 48 |
+
to_chars_result to_chars(char* first, char* last, long double value);
|
| 49 |
+
```
|
| 50 |
+
|
| 51 |
+
*Effects:* `value` is converted to a string in the style of `printf` in
|
| 52 |
+
the `"C"` locale. The conversion specifier is `f` or `e`, chosen
|
| 53 |
+
according to the requirement for a shortest representation (see above);
|
| 54 |
+
a tie is resolved in favor of `f`.
|
| 55 |
+
|
| 56 |
+
*Throws:* Nothing.
|
| 57 |
+
|
| 58 |
+
``` cpp
|
| 59 |
+
to_chars_result to_chars(char* first, char* last, float value, chars_format fmt);
|
| 60 |
+
to_chars_result to_chars(char* first, char* last, double value, chars_format fmt);
|
| 61 |
+
to_chars_result to_chars(char* first, char* last, long double value, chars_format fmt);
|
| 62 |
+
```
|
| 63 |
+
|
| 64 |
+
*Requires:* `fmt` has the value of one of the enumerators of
|
| 65 |
+
`chars_format`.
|
| 66 |
+
|
| 67 |
+
*Effects:* `value` is converted to a string in the style of `printf` in
|
| 68 |
+
the `"C"` locale.
|
| 69 |
+
|
| 70 |
+
*Throws:* Nothing.
|
| 71 |
+
|
| 72 |
+
``` cpp
|
| 73 |
+
to_chars_result to_chars(char* first, char* last, float value,
|
| 74 |
+
chars_format fmt, int precision);
|
| 75 |
+
to_chars_result to_chars(char* first, char* last, double value,
|
| 76 |
+
chars_format fmt, int precision);
|
| 77 |
+
to_chars_result to_chars(char* first, char* last, long double value,
|
| 78 |
+
chars_format fmt, int precision);
|
| 79 |
+
```
|
| 80 |
+
|
| 81 |
+
*Requires:* `fmt` has the value of one of the enumerators of
|
| 82 |
+
`chars_format`.
|
| 83 |
+
|
| 84 |
+
*Effects:* `value` is converted to a string in the style of `printf` in
|
| 85 |
+
the `"C"` locale with the given precision.
|
| 86 |
+
|
| 87 |
+
*Throws:* Nothing.
|
| 88 |
+
|
| 89 |
+
ISO C 7.21.6.1.
|
| 90 |
+
|