xnu-4903.221.2.tar.gz

[apple/xnu.git] / osfmk / man / DP_backing_store_info.html

<h2>default_pager_backing_store_info</h2>
<hr>
<p>
<strong>Server Interface</strong> - Return information about a backing storage object.
<h3>SYNOPSIS</h3>
<pre>
<strong>#include&lt default_pager/mach/default_pager_types.h&gt</strong>

<strong>kern_return_t   default_pager_backing_store_info</strong>
                <strong>(mach_port_t</strong>                      <var>backing_store</var>,
                 <strong>backing_store_flavor_t</strong>                  <var>flavor</var>,
                 <strong>backing_store_info_t</strong>                      <var>info</var>,
                 <strong>mach_msg_type_number_t</strong>                    <var>size</var><strong>);</strong>
</pre>
<h3>PARAMETERS</h3>
<dl>
<p>
<dt> <var>backing_store</var>
<dd>
[in backing store (receive) right] The backing store port for which
information is desired.
<p>
<dt> <var>flavor</var>
<dd>
[in scalar] The type of information to be returned. Valid values are:
<p>
<dt> <var>BACKING_STORE_BASIC_INFO</var>
<dd>
Statistical and space used/available information. It includes 
the priority and cluster size that was provided in the 
default_pager_backing_store_create call.
<p>
<dt> <var>info</var>
<dd>
[pointer to in structure] The data structure that will be filled in with the 
information provided for the requested flavor.
<p>
<dt> <var>size</var>
<dd>
[pointer to in/out scalar] On input, the maximum size of the info data 
structure; on output, the actual size of the returned data.
</dl>
<h3>DESCRIPTION</h3>
<p>
The <strong>default_pager_backing_store_info</strong> function is called to obtain
information about a backing storage object created by
<strong>default_pager_backing_store_create</strong>. The kernel does not make this call
itself (which is why it can be a synchronous call); this request is
only issued by tasks holding the backing store port, created with
<strong>default_pager_backing_store_create</strong>, for a default memory manager.
<h3>RETURN VALUES</h3>
<dl>
<p>
<dt> <strong>KERN_FAILURE</strong>
<dd>
The default pager does not support this operation.
<p>
<dt> <strong>KERN_INVALID_ARGUMENT</strong>
<dd>
The backing_store port does not represent a valid backing store, flavor 
is not valid, or size is not the size for the requested flavor.
<p>
<dt> <strong>KERN_SUCCESS</strong>
<dd>
The operation was successful.
</dl>
<h3>RELATED INFORMATION</h3>
<p>
Functions:
<a href="DP_backing_store_create.html"><strong>default_pager_backing_store_create</strong></a>,
<a href="DP_backing_store_delete.html"><strong>default_pager_backing_store_delete</strong></a>.
<p>
Data Structures:
backing_store_basic_info.