name: duk_is_undefined

proto: |
  duk_bool_t duk_is_undefined(duk_context *ctx, duk_idx_t index);

stack: |
  [ ... val! ... ]

summary: |
  <p>Returns 1 if value at <code>index</code> is either <code>undefined</code>, otherwise
  returns 0.  If <code>index</code> is invalid, also returns 0.</p>

example: |
  if (duk_is_undefined(ctx, -3)) {
      /* ... */
  }

tags:
  - stack

introduced: 1.0.0