*nix Documentation Project
·  Home
 +   man pages
·  Linux HOWTOs
·  FreeBSD Tips
·  *niX Forums

  man pages->FreeBSD man pages -> core (5)              



NAME    [Toc]    [Back]

     core -- memory image file format

SYNOPSIS    [Toc]    [Back]

     #include <sys/param.h>

DESCRIPTION    [Toc]    [Back]

     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 available debuggers.  (See
     sigaction(2).)  This memory image is written to a file named by default
     programname.core in the working directory; provided the terminated
     process had write permission in the directory, 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.

     The name of the file is controlled via the sysctl(8) variable
     kern.corefile.  The contents of this variable describes a filename to
     store the core image to.  This filename can be absolute, or relative
     (which will resolve to the current working directory of the program generating
 it).  Any sequence of %N in this filename template will be
     replaced by the process name, %P by the processes PID, and %U by the UID.
     The name defaults to %N.core, yielding the traditional FreeBSD behaviour.

     By default, a process that changes user or group credentials whether real
     or effective will not create a corefile.  This behaviour can be changed
     to generate a core dump by setting the sysctl(8) variable
     kern.sugid_coredump to 1.

     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 PAGE_SIZE (also
     from <sys/param.h>).

EXAMPLES    [Toc]    [Back]

     In order to store all core images in per-user private areas under
     /var/coredumps, the following sysctl(8) command can be used:

	   sysctl kern.corefile="/var/coredumps/%U/%N.core"

SEE ALSO    [Toc]    [Back]

     gdb(1), kgdb(1), setrlimit(2), sigaction(2), sysctl(8)

HISTORY    [Toc]    [Back]

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

FreeBSD 5.2.1			January 9, 2002 		 FreeBSD 5.2.1
[ Back ]
 Similar pages
Name OS Title
core Tru64 Format of memory image file
iflXBM IRIX XBM format image file
iflSGI IRIX SGI format image file
iflRaw IRIX raw image file format
iflXPM IRIX XPM format image file
iflYUV IRIX YUV format image file
iflGIF IRIX GIF format image file
iflFormat IRIX abstraction of an image file format
iflSOFTIMAGE IRIX SOFTIMAGE format image file
iflAlias IRIX Alias format image file
Copyright © 2004-2005 DeniX Solutions SRL
newsletter delivery service