strtoul(3)                                                   strtoul(3)

  strtoul()

  NAME

    strtoul() - convert a string to an unsigned long

  SYNOPSIS

    #include 
    #include 

    unsigned long strtoul (const char *nptr, char **endptr, int base)

  DESCRIPTION

    The strtoul(3) function converts the string in nptr to an unsigned long
    value. The conversion is done according to the given base, which must be
    between 2 and 36 inclusive, or be the special value 0.

    The string may begin with an arbitrary amount of white space (as
    determined by isspace(3)) followed by a single optional + or - sign. If
    base is zero or 16, the string may then include a 0x prefix, and the
    number will be read in base 16; otherwise, a zero base is taken as 10
    (decimal) unless the next character is 0, in which case it is taken as 8
    (octal).

    The remainder of the string is converted to an unsigned long value in the
    obvious manner, stopping at the end of the string or at the first
    character that does not produce a valid digit in the given base. (In bases
    above 10, the letter A in either upper or lower case represents 10, B
    represents 11, and so forth, with Z representing 35.)

    If endptr is not nil, strtoul(3) stores the address of the first invalid
    character in *endptr. If there were no digits at all, however, strtoul(3)
    stores the original value of nptr in *endptr. (Thus, if *nptr is not \0
    but **endptr is \0 on return, the entire string was valid.)

  RETURN VALUES

    The strtoul(3) function returns either the result of the conversion or, if
    there was a leading minus sign, the negation of the result of the
    conversion, unless the original (non-negated) value would overflow; in the
    latter case, strtoul(3) returns {ULONG_MAX} and sets the global variable
    errno to [ERANGE].

  ERRORS

    [ERANGE]
        The given string was out of range; the value converted has been
        clamped.

  SEE ALSO

    strtol(3)

  USAGE NOTES

    The strtoul function is thread safe.

    The strtoul function is not async-signal safe.