NAME¶

std::wcstoul,std::wcstoull - std::wcstoul,std::wcstoull

Synopsis¶

Defined in header <cwchar>
unsigned long wcstoul ( const wchar_t* str, wchar_t** str_end,
int base );
unsigned long long wcstoull( const wchar_t* str, wchar_t** str_end, (since C++11)
int base );

Interprets an unsigned integer value in a wide string pointed to by str.

Discards any whitespace characters (as identified by calling std::iswspace) until
the first non-whitespace character is found, then takes as many characters as
possible to form a valid base-n (where n=base) unsigned integer number
representation and converts them to an integer value. The valid unsigned integer
value consists of the following parts:

* (optional) plus or minus sign
* (optional) prefix (0) indicating octal base (applies only when the base is 8 or
0)
* (optional) prefix (0x or 0X) indicating hexadecimal base (applies only when the
base is 16 or 0)
* a sequence of digits

The set of valid values for base is {0,2,3,...,36}. The set of valid digits for
base-2 integers is {0,1}, for base-3 integers is {0,1,2}, and so on. For bases
larger than 10, valid digits include alphabetic characters, starting from Aa for
base-11 integer, to Zz for base-36 integer. The case of the characters is ignored.

Additional numeric formats may be accepted by the currently installed C locale.

If the value of base is 0, the numeric base is auto-detected: if the prefix is 0,
the base is octal, if the prefix is 0x or 0X, the base is hexadecimal, otherwise the
base is decimal.

If the minus sign was part of the input sequence, the numeric value calculated from
the sequence of digits is negated as if by unary minus in the result type, which
applies unsigned integer wraparound rules.

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 a null pointer, it is ignored.

Parameters¶

str - pointer to the null-terminated wide string to be interpreted
str_end - pointer to a pointer to a wide character
base - base of the interpreted integer value

Return value¶

Integer 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
ULONG_MAX or ULLONG_MAX is returned. If no conversion can be performed, 0 is
returned.

Example¶

// Run this code

#include <cwchar>
#include <errno.h>
#include <iostream>
#include <string>

int main()
{
const wchar_t* p = L"10 200000000000000000000000000000 30 40";
wchar_t* end;
std::wcout << "Parsing L'" << p << "':\n";
for (unsigned long i = std::wcstoul(p, &end, 10);
p != end;
i = std::wcstoul(p, &end, 10))
{
std::wcout << '\'' << std::wstring(p, end - p) << "' -> ";
p = end;
if (errno == ERANGE)
{
std::wcout << "range error, got ";
errno = 0;
}
std::wcout << i << '\n';
}
}

Possible output:¶

Parsing L'10 200000000000000000000000000000 30 40':
'10' -> 10
' 200000000000000000000000000000' -> range error, got 18446744073709551615
' 30' -> 30
' 40' -> 40

See also¶

strtoul converts a byte string to an unsigned integer value
strtoull (function)
(C++11)
wcstol converts a wide string to an integer value
wcstoll (function)
C documentation for
wcstoul,
wcstoull