# wcstoul

## PROLOG



           This manual page is part of the POSIX Programmer's Manual.  The
           Linux implementation of this interface may differ (consult the
           corresponding Linux manual page for details of Linux behavior), or
           the interface may not be implemented on Linux.
    


## NAME



           wcstoul, wcstoull — convert a wide-character string to an 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 functionality described on this reference page is aligned with
           the ISO C standard. Any conflict between the requirements
           described here and the ISO C standard is unintentional. This
           volume of POSIX.1‐2017 defers to the ISO C standard.
    
           The _wcstoul_() and _wcstoull_() functions shall convert the initial
           portion of the wide-character string pointed to by _nptr_ to
           **unsigned long** and **unsigned long long** representation, respectively.
           First, they shall decompose the input wide-character string into
           three parts:
    
            1. An initial, possibly empty, sequence of white-space wide-
               character codes (as specified by _iswspace_())
    
            2. A subject 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
    
           Then they shall attempt to convert the subject sequence to an
           unsigned integer, and return the result.
    
           If _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 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 **'-'** 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_ shall be 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 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 white space is other than a sign or a permissible
           letter or digit.
    
           If the subject sequence has the expected form and _base_ is 0, the
           sequence of wide-character codes starting with the first digit
           shall be interpreted as an integer constant. If the subject
           sequence has the expected form and the value of _base_ is between 2
           and 36, it shall be used as the base for conversion, ascribing to
           each letter its value as given above. If the subject sequence
           begins with a <hyphen-minus>, the value resulting from the
           conversion shall be negated. A pointer to the final wide-character
           string shall be stored in the object pointed to by _endptr_ ,
           provided that _endptr_ is not a null pointer.
    
           In other than the C or POSIX locale, additional locale-specific
           subject sequence forms may be accepted.
    
           If the subject sequence is empty or does not have the expected
           form, no conversion shall be performed; the value of _nptr_ shall be
           stored in the object pointed to by _endptr_ , provided that _endptr_ is
           not a null pointer.
    
           These functions shall 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 wishing to check
           for error situations should set _errno_ to 0, then call _wcstoul_() or
           _wcstoull_(), then check _errno_.
    


## RETURN VALUE



           Upon successful completion, the _wcstoul_() and _wcstoull_() functions
           shall return the converted value, if any. If no conversion could
           be performed, 0 shall be 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
           shall be returned and _errno_ set to **[ERANGE]**.
    


## ERRORS



           These functions shall fail if:
    
           **EINVAL** The value of _base_ is not supported.
    
           **ERANGE** The value to be returned is not representable.
    
           These functions may fail if:
    
           **EINVAL** No conversion could be performed.
    
           _The following sections are informative._
    


## EXAMPLES



           None.
    


## APPLICATION USAGE



           None.
    


## RATIONALE



           None.
    


## FUTURE DIRECTIONS



           None.
    


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