wcstoul(3C) Standard C Library Functions wcstoul(3C)NAME
wcstoul, wcstoull - convert wide-character string to unsigned long
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);
DESCRIPTION
The wcstoul() and wcstoull() functions convert the initial portion of
the wide-character string pointed to by nptr to unsigned long and
unsigned long long representation, respectively. First they decompose
the input wide-character string into three parts:
1. An initial, possibly empty, sequence of white-space wide-character
codes (as specified by the function iswspace(3C))
2. Asubject 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
They then attempt to convert the subject sequence to an unsigned inte‐
ger and return the result.
If the value of base is 0, the expected form of the subject sequence is
that of a decimal constant, an octal constant, or a hexadecimal con‐
stant, any of which may be preceded by a `+' or a `−' 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', option‐
ally followed by a sequence of the digits `0' to `7' only. A hexadeci‐
mal 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 sub‐
ject sequence is a sequence of letters and digits representing an inte‐
ger with the radix specified by base, optionally preceded by a `+' or
a `−' 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 are per‐
mitted. If the value of base is 16, the wide-character codes `0x' or
`0X' may optionally precede the sequence of letters and digits, follow‐
ing 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 a 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 a white space
is other than a sign or a permissible letter or digit.
If the subject sequence has the expected form and the value of base is
0, the sequence of wide-character codes starting with the first digit
is interpreted as an integer constant. If the subject sequence has the
expected form and the value of base is between 2 and 36, it is used as
the base for conversion, ascribing to each letter its value as given
above. If the subject sequence begins with a minus sign, the value
resulting from the conversion is negated. A pointer to the final wide
character string is stored in the object pointed to by endptr, pro‐
vided that endptr is not a null pointer.
If the subject sequence is empty or does not have the expected form, no
conversion is performed; the value of nptr is stored in the object
pointed to by endptr, provided that endptr is not a null pointer.
The wcstoul() function does not change the setting of errno if success‐
ful.
Since 0, {ULONG_MAX}, and {ULLONG_MAX} are returned on error and 0 is
also a valid return on success, an application wanting to check for
error situations should set errno to 0, then call wcstoul() or
wcstoull(), then check errno.
The wcstoul() and wcstoull() functions do not change the setting of
errno if successful.
RETURN VALUE
Upon successful completion, wcstoul() and wcstoull() return the con‐
verted value, if any. If no conversion could be performed, 0 is
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, is returned and errno is set to ERANGE.
ERRORS
The wcstoul() and wcstoull() functions will fail if:
EINVAL The value of base is not supported.
ERANGE The value to be returned is not representable.
The wcstoul() and wcstoull() functions may fail if:
EINVAL No conversion could be performed.
USAGE
Unlike wcstod(3C) and wcstol(3C), wcstoul() and wcstoull() must always
return a non-negative number; using the return value of wcstoul() for
out-of-range numbers with wcstoul() or wcstoull() could cause more
severe problems than just loss of precision if those numbers can ever
be negative.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Interface Stability │Standard │
├─────────────────────────────┼─────────────────────────────┤
│MT-Level │MT-Safe │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOisspace(3C), iswalpha(3C), scanf(3C), wcstod(3C), wcstol(3C),
attributes(5), standards(5)SunOS 5.10 1 Nov 2003 wcstoul(3C)
