NAME

       strtoul, strtoull - convert a string to an unsigned long

SYNOPSIS

       #include <stdlib.h>

       unsigned long strtoul(const char *restrict str,
              char **restrict endptr, int base);
       unsigned long long strtoull(const char *restrict str,
              char **restrict endptr, int base);

DESCRIPTION

       These functions shall convert the initial portion of the string pointed to by str to a type unsigned long
       and  unsigned  long  long representation, respectively. First, they decompose the input string into three
       parts:

        1. An initial, possibly empty, sequence of white-space characters (as specified by isspace())

        2. A subject sequence interpreted as an integer represented in some radix determined  by  the  value  of
           base

        3. A  final  string  of  one or more unrecognized characters, including the terminating null byte of the
           input string

       Then they shall 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, 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. 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  characters 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 string, starting with the
       first non-white-space character that is of the expected form.  The  subject  sequence  shall  contain  no
       characters  if  the input string is empty or consists entirely of white-space characters, or if the first
       non-white-space character 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  characters
       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 minus sign,  the
       value  resulting  from  the conversion shall be negated. A pointer to the final 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  locales, other implementation-defined subject sequences may be accepted.

       If the subject sequence is empty or does not have the expected form, no conversion  shall  be  performed;
       the  value  of str shall be stored in the object pointed to by endptr, provided that endptr is not a null
       pointer.

       The strtoul() function shall not change the setting of errno if successful.

       Since 0, {ULONG_MAX}, and {ULLONG_MAX} are returned on error and are also valid returns  on  success,  an
       application  wishing  to  check  for  error  situations  should  set  errno  to 0, then call strtoul() or
       strtoull(), then check errno.

RETURN VALUE

       Upon successful completion, these functions shall return the converted value, if any.  If  no  conversion
       could  be  performed,  0  shall be returned    and errno may be set to [EINVAL].  If the correct value is
       outside the range of representable values, {ULONG_MAX} or {ULLONG_MAX} 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.

SEE ALSO

       isalpha() , scanf() , strtod()  ,  strtol()  ,  the  Base  Definitions  volume  of  IEEE Std 1003.1-2001,
       <stdlib.h>

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition,
       Standard  for  Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base
       Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics Engineers,
       Inc and The Open Group. In the event of any discrepancy between this version and the  original  IEEE  and
       The  Open  Group  Standard,  the  original  IEEE and The Open Group Standard is the referee document. The
       original Standard can be obtained online at http://www.opengroup.org/unix/online.html .

IEEE/The Open Group                                   2003                                            STRTOUL(P)