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

<h2>vm_deallocate</h2>\r<hr>\r<p>\r<strong>Function</strong> - Deallocate a region of virtual memory.\r<h3>SYNOPSIS</h3>\r<pre>\r<strong>kern_return_t   vm_deallocate</strong>\r                <strong>(vm_task_t</strong>                          <var>target_task</var>,\r                 <strong>vm_address_t</strong>                           <var>address</var>,\r                 <strong>vm_size_t</strong>                                 <var>size</var><strong>);</strong>\r</pre>\r<h3>PARAMETERS</h3>\r<dl>\r<p>\r<dt> <var>target_task</var> \r<dd>\r[in task send right]\rThe port for the task in whose address space the\rregion is to be deallocated.\r<p>\r<dt> <var>address</var> \r<dd>\r[in scalar]\rThe starting address for the region.\r<p>\r<dt> <var>size</var> \r<dd>\r[in scalar]\rThe number of bytes to deallocate.\r</dl>\r<h3>DESCRIPTION</h3>\r<p>\rThe <strong>vm_deallocate</strong> function deallocates a region of\rvirtual memory in the\rspecified task's address space.\rThe region starts at the beginning of the virtual page containing\r<var>address</var> and ends \rat the end of the virtual page containing <var>address</var>\r+ <var>size</var> - 1.  Because of this \rrounding to virtual page boundaries, the amount of memory deallocated may be \rgreater than <var>size</var>.  Use <strong>host_page_size</strong> \rto find the current virtual page size.\r<p>\r<strong>vm_deallocate</strong> affects only <var>target_task</var>.  Other tasks\rthat have access to the deallocated memory can continue to reference it.\r<h3>NOTES</h3>\r<p>\r<strong>vm_deallocate</strong> can be used to deallocate memory passed\ras out-of-line data in a \rmessage.\r<p>\rThis interface is machine word length specific because of the virtual address\rparameter.\r<h3>RETURN VALUES</h3>\r<dl>\r<p>\r<dt> <strong>KERN_INVALID_ADDRESS</strong>\r<dd>\rThe address is illegal or specifies a non-allocated region.\r</dl>\r<h3>RELATED INFORMATION</h3>\r<p>\rFunctions:\r<a href="mach_msg.html"><strong>mach_msg</strong></a>,\r<a href="vm_allocate.html"><strong>vm_allocate</strong></a>,\r<a href="vm_map.html"><strong>vm_map</strong></a>,\r<a href="host_page_size.html"><strong>host_page_size</strong></a>.\r