=proto
void duk_dup_top(duk_context *ctx);

=stack
[ ... val! ] -> [ ... val! val! ]

=summary
<p>Push a duplicate of the value at stack top to the stack.
If the value stack is empty, throws an error.</p>

<p>Equivalent to calling
<tt><a href="#duk_dup">duk_dup(ctx, -1)</a></tt>.</p>

=example
duk_push_int(ctx, 123);  /* -> [ ... 123 ] */
duk_push_int(ctx, 234);  /* -> [ ... 123 234 ] */
duk_dup_top(ctx, -2);    /* -> [ ... 123 234 234 ] */

=tags
stack