CORE

Section: File Formats (5)
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BSD mandoc
BSD 4

NAME

core - memory image file format

SYNOPSIS

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

HISTORY

A core file format appeared in AT&T System v6 .