NAME

core − format of memory image file

SYNOPSIS

#include <sys/core.h>

DESCRIPTION

The UNIX System writes out a memory image of a terminated process when any of various errors occur.  See 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).

The maximum size of a core file is limited by setrlimit(2). Files which would be larger than the limit are not created.

Set-user-id programs do not produce core files when they terminate as this would be a security loophole. 

The core file consists of a core structure defined in the <sys/core.h> file.  The core structure includes the registers, the floating point status, the program’s header, the size of the text, data, and stack segments, the name of the program and the number of the signal that terminated the process.  The program’s header is described by the exec structure defined in the <sys/exec.h> file.

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 bytes) by the c_dsize member of the core structure.  The amount of stack image in the core file is given (in bytes) by the c_ssize member of the core structure. 

SEE ALSO

adb(1), dbx(1), sigvec(2), setrlimit(2)

Sun Release 3.2  —  Last change: 11 September 1985