name: duk_opt_heapptr

proto: |
  void *duk_opt_heapptr(duk_context *ctx, duk_idx_t idx, void *def_value);

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

summary: |
  <p>Get a borrowed <code>void *</code> reference to a Duktape heap allocated
  value (object, buffer, string) at <code>idx</code>.  If the value is
  <code>undefined</code> or the index is invalid, <code>def_value</code>
  default value is returned.  In other cases (<code>null</code> or
  non-matching type) throws an error.</p>

  <div include="default-pointer-validity.html" />

example: |
  void *ptr;

  ptr = duk_opt_heapptr(ctx, 2, default_ptr);

tags:
  - stack
  - borrowed
  - heapptr

introduced: 2.1.0