CORE(5) BSD File Formats Manual CORE(5)NAMEcore — memory image file format
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 abnormal‐
ity 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 remain‐
der 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 ALSOadb(1), dbx(1), gdb(1), kgdb(1), sigaction(2), setrlimit(2)HISTORY
A core file format appeared in Version 6 AT&T UNIX.
4th Berkeley Distribution December 11, 1993 4th Berkeley Distribution