illumos: manual page: wcstoul.3c

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 integer
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 constant,
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', 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 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 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 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, provided
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
successful.

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 converted
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