CORE(5)             UNIX Programmer's Manual		  CORE(5)



NAME
     core - format of memory image file

SYNOPSIS
     #include <sys/param.h>

DESCRIPTION
     The UNIX System writes out a memory image of a terminated
     process when any of various errors occur.	See _s_i_g_v_e_c(2) for
     the list of reasons; the most common are memory violations,
     illegal instructions, bus errors, and user-generated quit
     signals.  The memory image is called `core' and is written
     in the process's working directory (provided it can be; nor-
     mal access controls apply).

     The core file consists of the _u. area, whose size (in 64
     byte `clicks') is defined by the USIZE manifest in the
     <_s_y_s/_p_a_r_a_m._h> file.  The _u. area starts with a _u_s_e_r struc-
     ture as given in <_s_y_s/_u_s_e_r._h>.  The rest of the _u. area con-
     sists of the kernel stack for the terminated process which
     includes (among other things) the processor registers at the
     time of the fault; see the system listings for the format of
     this area.  The remainder of the core file consists first of
     the data pages and then the stack pages of the process
     image.  The amount of data space image in the core file is
     given (in clicks) by the variable _u__d_s_i_z_e in the _u. area.
     If the text segment was not write-only and and shared it is
     included as the first _e_t_e_x_t bytes of the data image where
     _e_t_e_x_t is taken from the symbol table of the object file
     which generated the memory image.	The amount of stack image
     in the core file is given (in clicks) by the variable
     _u__s_s_i_z_e in the _u. area.

     In general the debugger _a_d_b(1) is sufficient to deal with
     core images.

SEE ALSO
     adb(1), sigvec(2), stack(5)

















Printed 11/26/99	January 26, 1987			1