osfmk/man/vm_write.html

   1 <h2>vm_write</h2>
<hr>
<p>
<strong>Function</strong> - Write data to the specified address in the target task's address space.
<h3>SYNOPSIS</h3>
<pre>
<strong>kern_return_t   vm_write</strong>
                <strong>(vm_task_t</strong>                          <var>target_task</var>,
                 <strong>vm_address_t</strong>                           <var>address</var>,
                 <strong>pointer_t</strong>                                 <var>data</var>,
                 <strong>mach_msg_type_number_t</strong>              <var>data_count</var><strong>);</strong>
</pre>
<h3>PARAMETERS</h3>
<dl>
<p>
<dt> <var>target_task</var> 
<dd>
[in task send right]
The port for the task whose memory is to be
written.
<p>
<dt> <var>address</var> 
<dd>
[in scalar]
The address at which to start the write.
<p>
<dt> <var>data</var> 
<dd>
[pointer to page aligned in array of bytes]
An array of data to be
written.
<p>
<dt> <var>data_count</var> 
<dd>
[in scalar]
The number of bytes in the array.
</dl>
<h3>DESCRIPTION</h3>
<p>
The <strong>vm_write</strong> function writes an array of data to a
task's virtual memory.  It
allows one task to write to another task's memory.
<p>
The result of <strong>vm_write</strong> is as if <var>target_task</var> had directly
written into the set of 
pages.  Hence, <var>target_task</var> must have write permission to the pages.
<h3>NOTES</h3>
<p>
This interface is machine word length specific because of the virtual address
parameter.
<h3>RETURN VALUES</h3>
<dl>
<p>
<dt> <strong>KERN_PROTECTION_FAILURE</strong>
<dd>
Specified memory is valid, but does not permit writing.
<p>
<dt> <strong>KERN_INVALID_ADDRESS</strong>
<dd>
The address is illegal or specifies a non-allocated region.
</dl>
<h3>RELATED INFORMATION</h3>
<p>
Functions:
<a href="vm_copy.html"><strong>vm_copy</strong></a>,
<a href="vm_protect.html"><strong>vm_protect</strong></a>,
<a href="vm_read.html"><strong>vm_read</strong></a>,
<a href="host_page_size.html"><strong>host_page_size</strong></a>.