<p>In C, what is the most efficient way to convert a string of hex digits into a binary <code>unsigned int</code> or <code>unsigned long</code>?</p>

<p>For example, if I have <code>0xFFFFFFFE</code>, I want an <code>int</code> with the base10 value <code>4294967294</code>.</p>

You want
```
strtol
```
or
```
strtoul
```
.  See also the
Unix man page