NAME

core − format of core image file

DESCRIPTION

The UNIX system writes out a core image of a terminated process when any of various errors occur.  See signal(2) for the list of reasons; the most common are memory violations, illegal instructions, bus errors, and user-generated quit signals.  The core image is called core and is written in the process’s working directory (provided it can be; normal access controls apply).  A process with an effective user ID different from the real user ID will not produce a core image. 

The first section of the core image is a copy of the system’s per-user data for the process, including the registers as they were at the time of the fault. 

The remainder of the core file represents the actual contents of the user’s core area when the core image was written.  If the text segment is read-only and shared, or separated from data space, it is not dumped. 

The format of the first section is defined in /usr/include/sys/ptrace.h. The structure ptrace_user is first.  This structure contains the file offsets of the following sections. 

Following the ptrace_user structure, there is an optional array of pt_mem_desc structures.   The number of which is in the ptrace_user structure.  The pt_mem_desc structure contains the type, size, and file offsets of the "optional memory" sections.  Following the array of pt_mem_desc structures are the data and stack regions.  The ptrace_user structure has file offsets and sizes for both of these regions. 

SEE ALSO

setuid(2), signal(2). 
sdb(1) in the CX/UX User’s Reference Manual. 

CX/UX Programmer’s Reference Manual