wcstoll - convert wide character string to long long integer

Syntax	#include <wchar.h> long long int wcstoll(const wchar_t * nptr, wchar_t ** endptr, int base);
Description	wcstoll() converts the initial portion of the wide character string pointed to by nptr to long  long int representation. The input wide character string is first decomposed into three parts: an initial, possibly empty, sequence of white-space wide-character codes (as specified by iswspace()), a subject sequence interpreted as an integer represented in some radix determined by the value of base, and 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. wcstoll() then attempts to convert the subject sequence to an integer, and returns the result. If the value of 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 through 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 are permitted. If the value of base is 16, the wide character code representations of 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 non-white-space wide character code that 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 non-white-space wide character code 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.
Return val.	Converted value
		if successful.
	0	if no conversion could be performed. errno is set to EINVAL if the value of base is not supported.
	LLONG_MAX, LLONG_MIN
		depending on the sign of the value, if the correct value is outside the range of representable values. errno is set to ERANGE to indicate an error
Notes	This version of the C runtime system only supports 1-byte characters as wide character codes. Since 0 is returned on error as well as when a valid return can be successfully represented, an application wishing to check for error situations should perform the following actions: set errno to 0, call wcstoll(), then check errno, and if it is not equal to 0, assume that an error has occurred.
See also	iswalpha(), iswspace(), scanf(), strtol(), strtoll(), strtoul(), strtoull(), wcstod(), wcstol(), wcstoul().