CORE(5)                   386BSD Programmer's Manual                   CORE(5)

NAME
     core - memory image file format

SYNOPSIS
     #include <sys/param.h>

DESCRIPTION
     A small number of signals which cause abnormal termination of a process
     also cause a record of the process's in-core state to be written to disk
     for later examination by one of the aviailable debuggers.  (See
     sigaction(2).)  This memory image is written to a file named
     progname.core in the working directory, where progname is replaced by the
     name of the program; provided the terminated process had write permission
     in the directory, the filesystem on which the working directory is on was
     not mounted with the option nocore (See mount(8)),  and provided the
     abnormality did not cause a system crash.  (In this event, the decision
     to save the core file is arbitrary, see savecore(8).)

     The maximum size of a core file is limited by setrlimit(2).  Files which
     would be larger than the limit are not created.  Also, the kernel tries
     hard to not overwrite an existing file unless it is in standard coredump
     format and was produced from the same program.

     The core file consists of the u. area, whose size (in pages) is defined
     by the UPAGES manifest in the <sys/param.h> file.  The u. area starts
     with a user structure as given in <sys/user.h>. The remainder of the core
     file consists of the data pages followed by the stack pages of the
     process image.  The amount of data space image in the core file is given
     (in pages) by the variable u_dsize in the u. area.  The amount of stack
     image in the core file is given (in pages) by the variable u_ssize in the
     u. area.  The size of a ``page'' is given by the constant NBPG (also from
     <sys/param.h>).

SEE ALSO
     adb(1),  dbx(1),  gdb(1),  kgdb(1),  sigaction(2),  setrlimit(2)

HISTORY
     A core file format appeared in Version 6 AT&T UNIX.

4th Berkeley Distribution       April 29, 1991                               1