### DESCRIPTION

The ` strtoul` function converts the string in * nptr* to an

.Vt "unsigned long" value. The ` strtoull` function converts the string in * nptr* to an

.Vt "unsigned long long" value. The ` strtoumax` function converts the string in * nptr* to an

.Vt uintmax_t value. The ` strtouq` function converts the string in * nptr* to a

.Vt u_quad_t 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

.Vt "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.)