bsd man page for strtoul

STRTOUL(3)						     Library Functions Manual							STRTOUL(3)

NAME
       strtoul - convert a string to an unsigned long

SYNOPSIS
       #include <stdlib.h>
       #include <limits.h>

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

DESCRIPTION
       The  strtoul()  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 repre-
       sents 10, `B' represents 11, and so forth, with `Z' representing 35.)

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

RETURN VALUES
       The strtoul() 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() 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)

STANDARDS
       The strtoul() function conforms to ANSI C X3.159-1989 (``ANSI C'').

BUGS
       Ignores the current locale.

4.4 Berkeley Distribution					 January 12, 1996							STRTOUL(3)