osfmk/man/vm_msync.html

   1 <h2>vm_msync</h2>
   2 <hr>
   3 <p>
   4 <strong>Function</strong> - Synchronize the specified region of virtual memory.
   5 <h3>SYNOPSIS</h3>
   6 <pre>
   7 <strong>kern_return_t   vm_msync</strong>
   8                 <strong>(vm_task_t</strong>                          <var>target_task</var>,
   9                  <strong>vm_address_t</strong>                           <var>address</var>,
  10                  <strong>vm_size_t</strong>                                 <var>size</var>,
  11                  <strong>target_task</strong>                         <var>sync_flags</var><strong>);</strong>
  12 </pre>
  13 <h3>PARAMETERS</h3>
  14 <dl>
  15 <p>
  16 <dt> <var>target_task</var>
  17 <dd>
  18 [in task send right]
  19 The port for the task whose address space contains
  20 the region.
  21 <p>
  22 <dt> <var>address</var>
  23 <dd>
  24 [in scalar]
  25 The starting address for the region.
  26 <p>
  27 <dt> <var>size</var>
  28 <dd>
  29 [in scalar]
  30 The number of bytes in the region.
  31 <p>
  32 <dt> <var>sync_flags</var>
  33 <dd>
  34 [in scalar]
  35 The bit-wise <strong>OR</strong> of flags affecting the synchronization.
  36 Specifying both <strong>VM_SYNC_SYNCHRONOUS</strong> and
  37 <strong>VM_SYNC_ASYNCHRONOUS</strong> is invalid.
  38 <dl>
  39 <p>
  40 <dt> <strong>VM_SYNC_INVALIDATE</strong>
  41 <dd>
  42 Flushes pages in the range.  Only precious pages are returned to
  43 the memory manager unless either <strong>VM_SYNC_SYNCHRONOUS</strong> or
  44 <strong>VM_SYNC_ASYNCHRONOUS</strong> is also set.
  45 <p>
  46 <dt> <strong>VM_SYNC_SYNCHRONOUS</strong>
  47 <dd>
  48 Writes dirty and precious pages back to the memory manager,
  49 waits for pages to reach backing storage.
  50 <p>
  51 <dt> <strong>VM_SYNC_ASYNCHRONOUS</strong>
  52 <dd>
  53 Writes dirty and precious pages back to the memory manager,
  54 returns without waiting for pages to reach backing storage.
  55 </dl>
  56 </dl>
  57 <h3>DESCRIPTION</h3>
  58 <p>
  59 The <strong>vm_msync</strong> function synchronizes the contents of
  60 a memory range with its
  61 backing store image by flushing or cleaning the contents of the
  62 specified range
  63 to the range's memory manager, engaging in a synchronization protocol with
  64 the manager (<strong>memory_object_synchronize</strong>).
  65 The client does not return from
  66 this call until the memory manager responds (to the kernel) with
  67 <strong>memory_object_synchronize_completed</strong>.
  68 <h3>NOTES</h3>
  69 <p>
  70 This interface is machine word length specific because of the virtual address
  71 parameter.
  72 <h3>RETURN VALUES</h3>
  73 <dl>
  74 <p>
  75 <dt> <strong>KERN_INVALID_ADDRESS</strong>
  76 <dd>
  77 The address is illegal or specifies a non-allocated region.
  78 </dl>
  79 <h3>RELATED INFORMATION</h3>
  80 <p>
  81 Functions:
  82 <a href="memory_object_synchronize.html"><strong>memory_object_synchronize</strong></a>,
  83 <a href="MO_SY_completed.html"><strong>memory_object_synchronize_completed</strong></a>.