1<h2>memory_object_data_unavailable</h2>
2<hr>
3<p>
4<strong>Function</strong> - Instruct kernel to zero-fill pages as requested data does not exist.
5<h3>SYNOPSIS</h3>
6<pre>
7<strong>kern_return_t   memory_object_data_unavailable</strong>
8                <strong>(memory_object_control_t</strong>         <var>memory_control</var>,
9                 <strong>vm_offset_t</strong>                             <var>offset</var>,
10                 <strong>vm_size_t</strong>                                 <var>size</var><strong>);</strong>
11</pre>
12<h3>PARAMETERS</h3>
13<dl>
14<p>
15<dt> <var>memory_control</var> 
16<dd>
17[in memory-cache-control send right]
18The memory cache control port 
19to be used by the memory manager for cache management requests. 
20This port is provided by the kernel in a <strong>memory_object_init</strong> or a 
21<strong>memory_object_create</strong> call.
22<p>
23<dt> <var>offset</var> 
24<dd>
25[in scalar]
26The offset within the memory object, in bytes.
27<p>
28<dt> <var>size</var> 
29<dd>
30[in scalar]
31The number of bytes of data (starting at <var>offset</var>).  The number 
32must convert to an integral number of memory object pages.
33</dl>
34<h3>DESCRIPTION</h3>
35<p>
36The <strong>memory_object_data_unavailable</strong> function indicates
37that the memory 
38manager cannot provide the kernel with the data requested for
39the given region. 
40Instead, the kernel should provide the data for this region.
41<p>
42A memory manager can use this call in any of the following situations:
43<ul>
44<li>
45When the object was created by the kernel 
46(via <strong>memory_object_create</strong>) and 
47the kernel has not yet provided data for the region (via either
48<strong>memory_object_data_initialize</strong> or <strong>memory_object_data_return</strong>).
49In this case, the
50object is a temporary memory object; the memory manager is the default 
51memory manager; and the kernel should provide zero-filled pages for the
52object.
53     <p>
54<li>
55When the object is a normal user-created memory object.  In this case, the 
56kernel should provide zero-filled pages for the region.
57</ul>
58<h3>RETURN VALUES</h3>
59<p>
60Only generic errors apply.
61<h3>RELATED INFORMATION</h3>
62<p>
63Functions:
64<a href="memory_object_create.html"><strong>memory_object_create</strong></a>,
65<a href="memory_object_data_error.html"><strong>memory_object_data_error</strong></a>,
66<a href="memory_object_data_request.html"><strong>memory_object_data_request</strong></a>,
67<a href="memory_object_data_supply.html"><strong>memory_object_data_supply</strong></a>.
68