xnu-792.6.76.tar.gz

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

<h2>default_pager_object_create</h2>
<hr>
<p>
<strong>Server Interface</strong> - Initialize a non-persistent memory object suitable for sharing between tasks.
<h3>SYNOPSIS</h3>
<pre>
<strong>kern_return_t   default_pager_object_create</strong>
                <strong>(mach_port_t</strong>                              <var>pager</var>,
                 <strong>memory_object_t</strong>                 <var>*memory_object</var>,
                 <strong>vm_size_t</strong>                          <var>object_size</var><strong>);</strong>


<strong>kern_return_t   seqnos_default_pager_object_create</strong>
                <strong>(mach_port_t</strong>                              <var>pager</var>,
                 <strong>mach_port_seqno_t</strong>                        <var>seqno</var>,
                 <strong>memory_object_t</strong>                 <var>*memory_object</var>,
                 <strong>vm_size_t</strong>                          <var>object_size</var><strong>);</strong>
</pre>
<h3>PARAMETERS</h3>
<dl>
<p>
<dt> <var>pager</var> 
<dd>
[in default-pager (receive) right]
The default memory manager service 
port.
<p>
<dt> <var>seqno</var> 
<dd>
[in scalar]
The sequence number of this message relative to the <var>pager</var> 
port.
<p>
<dt> <var>memory_object</var> 
<dd>
[out memory-object send right]
A memory object port (with full access) for the memory object.
<p>
<dt> <var>object_size</var> 
<dd>
[in scalar]
The maximum size for the memory object.
</dl>
<h3>DESCRIPTION</h3>
<p>
A <strong>default_pager_object_create</strong> function is called as
the result of a message
requesting that the default memory manager create and return a (shared) memory 
object which is suitable for use with <strong>vm_map</strong>.  This memory object has 
the same properties as does a memory object provided by 
<strong>vm_allocate</strong>: its initial 
contents are zero and the backing contents are temporary in that they do not
persist after the memory object is destroyed.  The memory object
is suitable for use 
as non-permanent shared memory.  The kernel does not make this call itself 
(which is why it can be a synchronous call); this request is only issued by
(privileged) tasks holding the default memory manager port. 
This call should be 
contrasted with the kernel's <strong>memory_object_create</strong> message, in which 
the memory cache object is already created and the identity of the abstract 
memory object is made known to the default manager.
<h3>RETURN VALUES</h3>
<p>
Only generic errors apply.
<h3>RELATED INFORMATION</h3>
<p>
Functions:
<a href="vm_map.html"><strong>vm_map</strong></a>,
<a href="HD_memory_manager.html"><strong>host_default_memory_manager</strong></a>,
<a href="memory_object_create.html"><strong>memory_object_create</strong></a>,
<a href="MO_default_server.html"><strong>memory_object_default_server</strong></a>,
<a href="SMO_default_server.html"><strong>seqnos_memory_object_default_server</strong></a>.