4.3BSD/usr/man/man5/core.5

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.\"	@(#)core.5	6.2 (Berkeley) 3/9/86
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.TH CORE 5  "March 9, 1986"
.UC 4
.SH NAME
core \- format of memory image file
.SH SYNOPSIS
.B #include <sys/param.h>
.SH DESCRIPTION
The UNIX System writes out a memory image of a terminated
process when any of various errors occur.  See
.IR sigvec (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; normal access controls apply).
.PP
The maximum size of a
.I core
file is limited by
.IR setrlimit (2).
Files which would be larger than the limit are not created.
.PP
The core file consists of the
.I u.
area, whose size (in pages) is
defined by the UPAGES manifest in the
.RI < sys/param.h >
file.  The 
.I u.
area starts with a 
.I user
structure as given in
.RI < sys/user.h >.
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 pages) by the
variable
.I u_dsize
in the
.I u.
area.
The amount of stack image in the core file is given (in pages) by the
variable 
.I u_ssize
in the 
.I u.
area.
The size of a ``page'' is given by the constant NBPG
(also from
.RI < sys/param.h >).
.PP
In general the debugger
.IR adb (1)
is sufficient to deal with core images.
.SH "SEE ALSO"
adb(1), dbx(1), sigvec(2), setrlimit(2)