std::wcstof, std::wcstod, std::wcstold
Defined in header
<cwchar>
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float wcstof( const wchar_t* str, wchar_t** str_end );
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(since C++11) | |
double wcstod( const wchar_t* str, wchar_t** str_end );
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long double wcstold( const wchar_t* str, wchar_t** str_end );
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(since C++11) | |
Interprets a floating point value in a wide string pointed to by str
.
Function discards any whitespace characters (as determined by std::isspace()) until first non-whitespace character is found. Then it takes as many characters as possible to form a valid floating point representation and converts them to floating point value. The valid floating point value can be one of the following:
- decimal floating point expression. It consists of the following parts:
-
- (optional) plus or minus sign
- nonempty sequence of decimal digits optionally containing decimal point character (as determined by the current C locale) (defines significand)
- (optional)
e
orE
followed with optional minus or plus sign and nonempty sequence of decimal digits (defines exponent)
- binary floating point expression. It consists of the following parts:
-
- (optional) plus or minus sign
-
0x
or0X
- nonempty sequence of hexadecimal digits optionally containing a decimal point character (as determined by the current C locale) (defines significand)
- (optional)
p
orP
followed with optional minus or plus sign and nonempty sequence of decimal digits (defines exponent)
- infinity expression. It consists of the following parts:
-
- (optional) plus or minus sign
-
INF
orINFINITY
ignoring case
- not-a-number expression. It consists of the following parts:
-
- (optional) plus or minus sign
-
NAN
orNAN(
char_sequence)
ignoring case of theNAN
part. char_sequence can only contain alphanumeric characters. The result is a quiet NaN floating point value.
- any other expression that may be accepted by the currently installed C locale
The functions sets the pointer pointed to by str_end
to point to the wide character past the last character interpreted. If str_end
is NULL, it is ignored.
Contents |
[edit] Parameters
str | - | pointer to the null-terminated wide string to be interpreted |
str_end | - | pointer to a pointer to a wide character. |
[edit] Return value
Floating point value corresponding to the contents of str
on success. If the converted value falls out of range of corresponding return type, range error occurs and HUGE_VAL, HUGE_VALF or HUGE_VALL is returned. If no conversion can be performed, 0 is returned.
[edit] Example
This section is incomplete Reason: no example |
[edit] See also
C documentation for wcstof
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