Search all pages
Professions, Sciences, Humanities, Business, ...
Text-based, GUI, Audio, Video, Keyboards, Mouse, Images,...
Conversions, tests, processing, manipulation,...
Integer, Floating point, Matrix, Statistics, Boolean, ...
Algorithms, Memory, Process control, Debugging, ...
Data storage, Integrity, Encryption, Compression, ...
Networks, protocols, Interprocess, Remote, Client Server, ...
Timing, Calendar and Clock, Audio, Video, Printer, Controls...
Management, Filtering, File & Directory access, Viewers, ...
RocketLink!--> Man page versions:
RFORK(2) OpenBSD Programmer's Manual RFORK(2)
rfork - manipulate process resources
Forking, vforking or rforking is the only way new processes are created.
The flags argument to rfork() selects which resources of the invoking
process (parent) are shared by the new process (child) or initialized to
their default values. The resources include the open file descriptor
table (which, when shared, permits processes to open and close files for
other processes), and open files. flags is the logical OR of some subset
RFPROC If set a new process is created; otherwise changes affect
the current process. The current implementation requires
this flag to always be set.
RFNOWAIT If set, the child process will be dissociated from the
parent. Upon exit the child will not leave a status for
the parent to collect. See wait(2).
RFNAMEG, RFCNAMEG, RFENVG, RFCENVG, RFNOTEG
These are Plan 9 specific flags, and not implemented.
RFFDG If set, the invoker's file descriptor table (see
intro(2)) is copied; otherwise the two processes share a
RFCFDG If set, the new process starts with a clean file descrip-
tor table. Is mutually exclusive with RFFDG.
RFMEM If set, the kernel will force sharing of the entire ad-
dress space. The child will then inherit all the shared
segments the parent process owns. Other segment types
will be unaffected. Subsequent forks by the parent will
then propagate the shared data and bss between children.
The stack segment is always split. May be set only with
File descriptors in a shared file descriptor table are kept open until
either they are explicitly closed or all processes sharing the table ex-
If RFPROC is set, the value returned in the parent process is the process
ID of the child process; the value returned in the child is zero. With-
out RFPROC, the return value is zero. Process ids range from 1 to the
maximum integer int value. rfork() will sleep, if necessary, until re-
quired process resources are available.
fork() can be implemented as a call to rfork(2) using "RFFDG|RFPROC" but
isn't for backwards compatibility. If a process has file descriptor
table sharing active, setuid or setgid programs will not execve(2) with
rfork() will fail and no child process will be created if:
[EAGAIN] The system-imposed limit on the total number of processes
under execution would be exceeded. This limit is configu-
[EAGAIN] The system-imposed limit MAXUPRC (<sys/param.h>) on the to-
tal number of processes under execution by a single user
would be exceeded.
[ENOMEM] There is insufficient swap space for the new process.
fork(2), intro(2), minherit(2), vfork(2)
The rfork() function first appeared in Plan9.
OpenBSD 2.6 January 12, 1996 2
Source: OpenBSD 2.6 man pages. Copyright: Portions are copyrighted by BERKELEY
SOFTWARE DESIGN, INC., The Regents of the University of California, Massachusetts
Institute of Technology, Free Software Foundation, FreeBSD Inc., and others.
(Corrections, notes, and links courtesy of RocketAware.com)
Up to: Process Limits: Resources - Process Limits on resource usage (disk, CPU, memory, et al)
RocketLink!--> Man page versions:
Search | About | Comments | Submit Path: RocketAware > man pages >
RocketAware.com is a service of Mib Software
Copyright 1999, Forrest J. Cavalier III. All Rights Reserved.
We welcome submissions and comments