std::wcstoul,std::wcstoull(3)

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