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STRTOUL(3P)                POSIX Programmer's Manual               STRTOUL(3P)

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
       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 representa-
       tion, 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 fol-
       lowed by a sequence of the digits '0' to '7' only.  A hexadecimal  con-
       stant  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 sub-
       ject sequence is a sequence of letters and digits representing an inte-
       ger  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,  pro-
       vided 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 suc-
       cessful.
       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  str-
       toull(), 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(3P)