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

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

=summary
<p>
Normalize argument index relative to the bottom of the current frame.
The resulting index will be 0 or greater and will be independent of
later stack modifications.  If the input index is invalid, throws
an error.</p>

=example
int idx = duk_require_normalize_index(-3);

=tags
stack

=seealso
duk_normalize_index