STRTOUL(3) UNIX Programmer's Manual STRTOUL(3) NAME strtoul - convert a string to an unsigned long SYNOPSIS #include #include unsigned long strtoul(nptr, endptr, base) _c_h_a_r *_n_p_t_r; _c_h_a_r **_e_n_d_p_t_r; _i_n_t _b_a_s_e; DESCRIPTION The strtoul() function converts the string in _n_p_t_r to an _u_n_s_i_g_n_e_d _l_o_n_g value. The conversion is done according to the given _b_a_s_e, 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 _b_a_s_e is zero or 16, the string may then include a `0x' prefix, and the number will be read in base 16; otherwise, a zero _b_a_s_e 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 _u_n_s_i_g_n_e_d _l_o_n_g 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 _e_n_d_p_t_r is non nil, strtoul() stores the address of the first invalid character in *_e_n_d_p_t_r . If there were no digits at all, however, strtoul() stores the original value of _n_p_t_r in *_e_n_d_p_t_r . (Thus, if *_n_p_t_r is not `\0' but **_e_n_d_p_t_r is `\0' 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 nega- tion 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. Printed 11/26/99 January 12, 1996 1 STRTOUL(3) UNIX Programmer's Manual STRTOUL(3) SEE ALSO strtol(3) STANDARDS The strtoul() function conforms to ANSI C X3.159-1989 (``ANSI C''). BUGS Ignores the current locale. Printed 11/26/99 January 12, 1996 2