or positive
depending on whether its first argument is smaller, equal or greater
than its second argument. The hashing function returns a suitable
hash value for its argument.</p><p>If the <span class=syntax-token>errorcheck(</span><span class=nonterminal>fn</span><span class=syntax-token>)</span> attribute is provided for the <span class=machine><span class=font-tt>typedef</span></span> <span class=font-it>ty</span>,
the error checking function <span class=nonterminal>fn</span> is called each time a functi