CORE(5)                   OpenBSD 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 available debuggers (see
     sigaction(2)). This memory image is written to a file named
     programname.core in the working directory, provided the terminated pro-
     cess 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 programname.core file is limited by setrlimit(2).
     Files which would be larger than the limit are not created.

     The programname.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 programname.core file consists of the data pages followed by the
     stack pages of the process image.  The amount of data space image in the
     programname.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
     gdb(1), setrlimit(2), sigaction(2)

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

OpenBSD 3.0                    December 11, 1993                             1
