символьная строка в беззнаковое длинное (character string to an unsigned long)
Пролог (Prolog)
This manual page is part of the POSIX Programmer's Manual. The
Linux implementation of this interface may differ (consult the
corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.
Имя (Name)
wcstoul, wcstoull — convert a wide-character string to an
unsigned long
Синопсис (Synopsis)
#include <wchar.h>
unsigned long wcstoul(const wchar_t *restrict nptr,
wchar_t **restrict endptr, int base);
unsigned long long wcstoull(const wchar_t *restrict nptr,
wchar_t **restrict endptr, int base);
Описание (Description)
The functionality described on this reference page is aligned
with the ISO C standard. Any conflict between the requirements
described here and the ISO C standard is unintentional. This
volume of POSIX.1‐2017 defers to the ISO C standard.
The wcstoul() and wcstoull() functions shall convert the initial
portion of the wide-character string pointed to by nptr to
unsigned long and unsigned long long representation,
respectively. First, they shall decompose the input wide-
character string into three parts:
1. An initial, possibly empty, sequence of white-space wide-
character codes (as specified by iswspace())
2. A subject sequence interpreted as an integer represented in
some radix determined by the value of base
3. A final wide-character string of one or more unrecognized
wide-character codes, including the terminating null wide-
character code of the input wide-character string
Then they shall attempt to convert the subject sequence to an
unsigned integer, and return the result.
If base is 0, the expected form of the subject sequence is that
of a decimal constant, octal constant, or hexadecimal constant,
any of which may be preceded by a '+' or '-' sign. A decimal
constant begins with a non-zero digit, and consists of a sequence
of decimal digits. An octal constant consists of the prefix '0'
optionally followed by a sequence of the digits '0' to '7' only.
A hexadecimal constant consists of the prefix 0x or 0X followed
by a sequence of the decimal digits and letters 'a' (or 'A') to
'f' (or 'F') with values 10 to 15 respectively.
If the value of base is between 2 and 36, the expected form of
the subject sequence is a sequence of letters and digits
representing an integer with the radix specified by base,
optionally preceded by a '+' or '-' sign, but not including an
integer suffix. The letters from 'a' (or 'A') to 'z' (or 'Z')
inclusive are ascribed the values 10 to 35; only letters whose
ascribed values are less than that of base shall be permitted. If
the value of base is 16, the wide-character codes 0x or 0X may
optionally precede the sequence of letters and digits, following
the sign if present.
The subject sequence is defined as the longest initial
subsequence of the input wide-character string, starting with the
first wide-character code that is not white space and is of the
expected form. The subject sequence contains no wide-character
codes if the input wide-character string is empty or consists
entirely of white-space wide-character codes, or if the first
wide-character code that is not white space is other than a sign
or a permissible letter or digit.
If the subject sequence has the expected form and base is 0, the
sequence of wide-character codes starting with the first digit
shall be interpreted as an integer constant. If the subject
sequence has the expected form and the value of base is between 2
and 36, it shall be used as the base for conversion, ascribing to
each letter its value as given above. If the subject sequence
begins with a <hyphen-minus>, the value resulting from the
conversion shall be negated. A pointer to the final wide-
character string shall be stored in the object pointed to by
endptr, provided that endptr is not a null pointer.
In other than the C or POSIX locale, additional locale-specific
subject sequence forms may be accepted.
If the subject sequence is empty or does not have the expected
form, no conversion shall be performed; the value of nptr shall
be stored in the object pointed to by endptr, provided that
endptr is not a null pointer.
These functions shall not change the setting of errno if
successful.
Since 0, {ULONG_MAX}, and {ULLONG_MAX} are returned on error and
0 is also a valid return on success, an application wishing to
check for error situations should set errno to 0, then call
wcstoul() or wcstoull(), then check errno.
Возвращаемое значение (Return value)
Upon successful completion, the wcstoul() and wcstoull()
functions shall return the converted value, if any. If no
conversion could be performed, 0 shall be returned and errno may
be set to indicate the error. If the correct value is outside
the range of representable values, {ULONG_MAX} or {ULLONG_MAX}
respectively shall be returned and errno set to [ERANGE].
Ошибки (Error)
These functions shall fail if:
EINVAL The value of base is not supported.
ERANGE The value to be returned is not representable.
These functions may fail if:
EINVAL No conversion could be performed.
The following sections are informative.
Примеры (Examples)
None.
Использование в приложениях (Application usage)
None.
Обоснование (Rationale)
None.
Будущие направления (Future directions)
None.
Смотри также (See also)
fscanf(3p), iswalpha(3p), wcstod(3p), wcstol(3p)
The Base Definitions volume of POSIX.1‐2017, wchar.h(0p)
