CORE(F)                              UNIX System V



     Name
          core - format of core image file


     Description
          The Operating System writes out a core image of a terminated
          process when any of various errors occur.  See signal(S) for
          the list of reasons; the most common are memory  violations,
          illegal  instructions,  bus  errors, and user-generated quit
          signals.  The core image is called core and  is  written  in
          the  process'  working directory (provided it can be; normal
          access controls apply).  A process with an effective user ID
          different  from  the  real  user  ID will not produce a core
          image.

          The first section of  the  core  image  is  a  copy  of  the
          system's  per-user  data  for  the  process,  including  the
          registers as they were at the time of the fault.   The  size
          of  this  section  depends  on the parameter usize, which is
          defined   in   /usr/include/sys/param.h.    The    remainder
          represents  the actual contents of the user's core area when
          the core image was written.  If the text  segment  is  read-
          only  and  shared,  or  separated from data space, it is not
          dumped.

          The format of  the  information  in  the  first  section  is
          described  by  the  user structure of the system, defined in
          /usr/include/sys/user.h.  The locations  of  registers,  are
          outlined in /usr/include/sys/reg.h.


     See Also
          adb(CP), setuid(S), signal(S)


     (printed 2/15/90)                                    CORE(F)