duktape/website/api/duk_to_pointer.txt

=proto
void *duk_to_pointer(duk_context *ctx, int index);

=stack
[ ... val! ... ] -> [ ... pointer(val)! ... ]

=summary
<p>Replaces the value at <tt>index</tt> with a pointer-coerced value.  Returns
the resulting <tt>void *</tt> value.  If <tt>index</tt> is invalid, throws an
error.</p>

<p>Coercion rules:</p>
<ul>
<li>Pointer: coerces to itself, no change</li>
<li>All heap allocated objects (string, object, buffer): coerce to a pointer
    which points to the Duktape internal heap header (use for debugging only,
    do not read/write)</li>
<li>Other types: coerces to NULL</li>
</ul>

<div class="note">
This API call is really only useful for debugging.  Note in particular that
the pointer returned must not be accessed, as it points to an internal heap
header.  This is the case even for string/buffer values: the returned pointer
differs from the one returned by <tt>duk_get_string()</tt> and
<tt>duk_get_buffer()</tt>.
</div>

=example
/* Don't dereference the pointer. */
printf("coerced pointer: %p\n", duk_to_pointer(ctx, -3));

=tags
stack