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core(5) [freebsd man page]

CORE(5) 						      BSD File Formats 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 by default 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 core file is limited by setrlimit(2). Files which would be larger than the limit are not created. The name of the file is controlled via the sysctl(8) variable kern.corefile. The contents of this variable describes a filename to store the core image to. This filename can be absolute, or relative (which will resolve to the current working directory of the program generating it). The following format specifiers may be used in the kern.corefile sysctl to insert additional information into the resulting core file name: %H Machine hostname. %I An index starting at zero until the sysctl debug.ncores is reached. This can be useful for limiting the number of corefiles generated by a particular process. %N process name. %P processes PID. %U process UID. The name defaults to %N.core, yielding the traditional FreeBSD behaviour. By default, a process that changes user or group credentials whether real or effective will not create a corefile. This behaviour can be changed to generate a core dump by setting the sysctl(8) variable kern.sugid_coredump to 1. Corefiles can be compressed by the kernel if the following items are included in the kernel configuration file: options COMPRESS_USER_CORES devices gzio When COMPRESS_USER_CORES is included the following sysctls can control if core files will be compressed: kern.compress_user_cores_gzlevel Gzip compression level. Defaults to -1. kern.compress_user_cores Actually compress user cores. Core files will have the suffix .gz appended to them. EXAMPLES
In order to store all core images in per-user private areas under /var/coredumps, the following sysctl(8) command can be used: sysctl kern.corefile=/var/coredumps/%U/%N.core SEE ALSO
gdb(1), kgdb(1), setrlimit(2), sigaction(2), sysctl(8) HISTORY
A core file format appeared in Version 6 AT&T UNIX. BSD
November 22, 2012 BSD

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gcore(1)						      General Commands Manual							  gcore(1)

NAME
gcore - get core images of running processes SYNOPSIS
filename] process-id... DESCRIPTION
The command creates a core image of each specified process. By default, the name of the core image file for process-id will be The process information in the core file can be obtained by using debuggers. When the command creates a core image of each specified process, the process is temporarily stopped. Further, when the creation of core image is complete, the process continues to execute. Options Creates the core file with name of the file as If multiple process-id values are specified, filename will be common for all the core image files. See the section. Operands process-id The process ID for which a core image file will be created. RETURN VALUE
Upon completion, exits with one of the following values: A core file was successfully created. An error condition was encountered. In such a case, the creation of a core file is not guaranteed. The error conditions could be because of o A nonexistent or incorrect process ID was specified. o An invalid option was specified. o The current working directory of the process or directory from which was invoked had no write permissions. o The current working directory of the process was not accessible. o The file system is full. EXAMPLES
Example 1 Dump the core image of process 1030 in the file "core.1030". Example 2 Dump the core image of the process 1030 in the file "test.1030". Example 3 Dump the core image of the processes 1030, 1031, 1032, and 1033 in the files "core.1030", "core.1031", "core.1032", "core.1033". Example 4 Dump the core image of the processes 1030, 1031, 1032, and 1033 in the files FILES
Core image file for process-id. (Both where is invoked and the current working directory of the process.) AUTHOR
was developed by Chris Bertin (HP). SEE ALSO
adb(1), gdb(1), kill(1), ttrace(2), a.out(4), core(4). gcore(1)
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