osfmk/man/exc_server.html

   1 <h2>exc_server</h2>
   2 <hr>
   3 <p>
   4 <strong>Function</strong> - Handle kernel-reported thread exception.
   5 <h3>SYNOPSIS</h3>
   6 <pre>
   7 <strong>boolean_t       exc_server</strong>
   8                 <strong>(mach_msg_header_t</strong>     <var>request_msg</var>,
   9                 <strong>mach_msg_header_t</strong>      <var>reply_ms</var><strong>);</strong>
  10 </pre>
  11 <h3>PARAMETERS</h3>
  12 <dl>
  13 <p>
  14 <dt> <var>in_msg</var>
  15 <dd>
  16 [pointer to in structure]
  17 The exception message received from the
  18 kernel.
  19 <p>
  20 <dt> <var>out_msg</var>
  21 <dd>
  22 [out structure]
  23 A reply message.
  24 </dl>
  25 <h3>DESCRIPTION</h3>
  26 <p>
  27 The <strong>exc_server</strong> function is the MIG generated server
  28 handling function to
  29 handle messages from the kernel relating to the occurrence of
  30 an exception in a
  31 thread.  Such messages are delivered to the exception port set via
  32 <strong>thread_set_exception_ports</strong> or <strong>task_set_exception_ports</strong>.
  33 When an exception occurs in a
  34 thread, the thread sends an exception message to its exception port, blocking in
  35 the kernel waiting for the receipt of a reply.  The <strong>exc_server</strong>
  36 function performs
  37 all necessary argument handling for this kernel message and calls
  38 <strong>catch_exception_raise</strong>, <strong>catch_exception_raise_state</strong> or
  39 <strong>catch_exception_raise_state_identity</strong>, which should handle the
  40 exception.  If the called routine
  41 returns <strong>KERN_SUCCESS</strong>, a reply message will be sent, allowing
  42 the thread to
  43 continue from the point of the exception; otherwise, no reply message is sent
  44 and the called routine must have dealt with the exception thread directly.
  45 <h3>RETURN VALUES</h3>
  46 <dl>
  47 <p>
  48 <dt> <strong>TRUE</strong>
  49 <dd>
  50 The message was handled and the appropriate function was called.
  51 <p>
  52 <dt> <strong>FALSE</strong>
  53 <dd>
  54 The message did not apply to the exception mechanism and no other
  55 action was taken.
  56 </dl>
  57 <h3>RELATED INFORMATION</h3>
  58 <p>
  59 Functions:
  60 <a href="catch_exception_raise.html"><strong>catch_exception_raise<strong></a>.