xref: /xnu-8796.121.2/osfmk/man/mach_msg_descriptor.html (revision c54f35ca767986246321eb901baf8f5ff7923f6a)

<h2>mach_msg_descriptor</h2>
<hr>
<p>
<strong>Structure</strong> - Specifies operations that must be performed on a given IPC message element.
<h3>SYNOPSIS</h3>
<pre>
<strong>typedef struct</strong>
<strong>{</strong>
       <strong>void*</strong>                             <var>pad1</var><strong>;</strong>
       <strong>mach_msg_size_t</strong>                   <var>pad2</var><strong>;</strong>
       <strong>unsigned int</strong>                      <var>pad3</var><strong> : 24;</strong>
       <strong>mach_msg_descriptor_type_t</strong>        <var>type</var><strong> : 8;</strong>
<strong>} mach_msg_type_descriptor_t;</strong>

<strong>typedef struct</strong>
<strong>{</strong>
       <strong>mach_port_t</strong>                       <var>name</var><strong>;</strong>
       <strong>mach_msg_size_t</strong>                   <var>pad1</var><strong>;</strong>
       <strong>unsigned int</strong>                      <var>pad2</var><strong> : 16;</strong>
       <strong>mach_msg_type_name_t</strong>       <var>disposition</var><strong> : 8;</strong>
       <strong>mach_msg_descriptor_type_t</strong>        <var>type</var><strong> : 8;</strong>
<strong>} mach_msg_port_descriptor_t;</strong>

<strong>typedef struct</strong>
<strong>{</strong>
       <strong>void*</strong>                          <var>address</var><strong>;</strong>
       <strong>mach_msg_size_t</strong>                   <var>size</var><strong>;</strong>
       <strong>boolean_t</strong>                   <var>deallocate</var><strong> : 8;</strong>
       <strong>mach_msg_copy_options_t</strong>           <var>copy</var><strong> : 8;</strong>
       <strong>unsigned int</strong>                      <var>pad1</var><strong> : 8;</strong>
       <strong>mach_msg_descriptor_type_t</strong>        <var>type</var><strong> : 8;</strong>
<strong>} mach_msg_ool_descriptor_t;</strong>

<strong>typedef struct</strong>
<strong>{</strong>
       <strong>void*</strong>                           <var>address</var><strong>;</strong>
       <strong>mach_msg_size_t</strong>                   <var>count</var><strong>;</strong>
       <strong>boolean_t</strong>                    <var>deallocate</var><strong> : 8;</strong>
       <strong>mach_msg_copy_options_t</strong>            <var>copy</var><strong> : 8;</strong>
       <strong>mach_msg_type_name_t</strong>        <var>disposition</var><strong> : 8;</strong>
       <strong>mach_msg_descriptor_type_t</strong>         <var>type</var><strong> : 8;</strong>
<strong>} mach_msg_ool_ports_descriptor_t;</strong>

<strong>typedef union</strong>
<strong>{</strong>
       <strong>mach_msg_port_descriptor_t</strong>             <var>port</var><strong>;</strong>
       <strong>mach_msg_ool_descriptor_t</strong>       <var>out_of_line</var><strong>;</strong>
       <strong>mach_msg_ool_ports_descriptor_t</strong>   <var>ool_ports</var><strong>;</strong>
       <strong>mach_msg_type_descriptor_t</strong>             <var>type</var><strong>;</strong>
<strong>} mach_msg_descriptor_t;</strong>
</pre>
<h3>FIELDS</h3>
<dl>
<dt> <var>name</var>
<dd>
For single port descriptors, the name of the port whose right is being
sent.
     <p>
<dt> <var>disposition</var>
<dd>
For single port or out-of-line port array descriptors, the IPC processing
to be done for the rights for the named ports.
     <p>
<dt> <var>address</var>
<dd>
For out-of-line data or port array descriptors, the address of the
out-of-line data or port (name) array.
     <p>
<dt> <var>size</var>
<dd>
For out-of-line data descriptors, the size of the out-of-line region, in
bytes.
     <p>
<dt> <var>deallocate</var>
<dd>
For out-of-line data descriptors, true if the set of pages containing the
array should be de-allocated when the message is sent.
     <p>
<dt> <var>copy</var>
<dd>
For out-of-line descriptors, a description of the method by which the
data should be copied.
     <p>
<dt> <var>count</var>
<dd>
For out-of-line port array descriptors, the number of port names in the
array.
     <p>
<dt> <var>type</var>
<dd>
For any type of descriptor, the type of descriptor.
     <p>
<dt> <var>port</var>
<dd>
A descriptor that describes a single port right.
     <p>
<dt> <var>out_of_line</var>
<dd>
A descriptor that describes an out-of-line data array.
     <p>
<dt> <var>ool_ports</var>
<dd>
A descriptor that describes an out-of-line port array.
</dl>
<h3>DESCRIPTION</h3>
<p>
A <strong>mach_msg_descriptor</strong> structure describes the processing
to be performed
for an element of kernel-processed data in a Mach message.
<h3>RELATED INFORMATION</h3>
<p>
Functions:
<a href="mach_msg.html"><strong>mach_msg</strong></a>.
<p>
Data Structures:
<a href="mach_msg_header.html"><strong>mach_msg_header</strong></a>.