=proto
int duk_require_boolean(duk_context *ctx, int index);

=stack
[ ... val! ... ]

=summary
<p>Like <tt><a href="#duk_get_boolean">duk_get_boolean()</a></tt>,
but throws an error if the value at <tt>index</tt> is not a boolean
or if the index is invalid.</p>

=example
if (duk_require_boolean(ctx, -3)) {
    printf("value is true\n");
}