osfmk/man/memory_object_data_error.html

   1 <h2>memory_object_data_error</h2>
   2 <hr>
   3 <p>
   4 <strong>Function</strong> - An error prevents the supply of previously requested data.
   5 <h3>SYNOPSIS</h3>
   6 <pre>
   7 <strong>kern_return_t   memory_object_data_error</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>,
  11                  <strong>kern_return_t</strong>                           <var>reason</var><strong>);</strong>
  12 </pre>
  13 <h3>PARAMETERS</h3>
  14 <dl>
  15 <p>
  16 <dt> <var>memory_control</var>
  17 <dd>
  18 [in memory-cache-control send right]
  19 The memory cache control port
  20 to be used by the memory manager for cache management requests.
  21 This port is provided by the kernel in a <strong>memory_object_create</strong> call.
  22 <p>
  23 <dt> <var>offset</var>
  24 <dd>
  25 [in scalar]
  26 The offset within the memory object, in bytes.
  27 <p>
  28 <dt> <var>size</var>
  29 <dd>
  30 [in scalar]
  31 The number of bytes of data (starting at <var>offset</var>).  The number
  32 must convert to an integral number of memory object pages.
  33 <p>
  34 <dt> <var>reason</var>
  35 <dd>
  36 [in scalar]
  37 Reason for the error.
  38 </dl>
  39 <h3>DESCRIPTION</h3>
  40 <p>
  41 The <strong>memory_object_data_error</strong> function indicates that
  42 the memory manager
  43 cannot provide the kernel with the data requested for the given region,
  44 specifying a reason for the error.
  45 <p>
  46 When the kernel issues a <strong>memory_object_data_request</strong> call, the memory
  47 manager can respond with a <strong>memory_object_data_error</strong>
  48 call to indicate that the
  49 page cannot be retrieved, and that a memory failure exception should be raised
  50 in any client threads that are waiting for the page.  Clients
  51 are permitted to catch
  52 these exceptions and retry their page faults.  As a result, this
  53 call can be used to
  54 report transient errors as well as permanent ones.  A memory manager can use
  55 this call for both hardware errors (for example, disk failures) and software
  56 errors (for example, accessing data that does not exist or is protected).
  57 <h3>NOTES</h3>
  58 <p>
  59 If reason has a system code of <var>err_kern</var>, the kernel will substitute
  60 an error value
  61 of <strong>KERN_MEMORY_ERROR</strong>.
  62 <h3>RETURN VALUES</h3>
  63 <p>
  64 Only generic errors apply.
  65 <h3>RELATED INFORMATION</h3>
  66 <p>
  67 Functions:
  68 <a href="memory_object_data_request.html"><strong>memory_object_data_request</strong></a>,
  69 <a href="memory_object_data_supply.html"><strong>memory_object_data_supply</strong></a>,
  70 <a href="MO_data_unavailable.html"><strong>memory_object_data_unavailable</strong></a>.