diff options
author | Niklas Hallqvist <niklas@cvs.openbsd.org> | 1996-01-14 01:27:18 +0000 |
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committer | Niklas Hallqvist <niklas@cvs.openbsd.org> | 1996-01-14 01:27:18 +0000 |
commit | 03ef4363369a9377d6c5e794aee682cb0c3e9c21 (patch) | |
tree | 98d582d8999297db2594d14b6c26da89427ed909 /lib | |
parent | 1b2c14105180551c765eaaeec49fe51420a7492e (diff) |
Redid formatting with mandoc macros. Added an "ERRORS" section.
Diffstat (limited to 'lib')
-rw-r--r-- | lib/libc/sys/rfork.2 | 120 |
1 files changed, 66 insertions, 54 deletions
diff --git a/lib/libc/sys/rfork.2 b/lib/libc/sys/rfork.2 index 0e4ad63486a..63ef078dd8e 100644 --- a/lib/libc/sys/rfork.2 +++ b/lib/libc/sys/rfork.2 @@ -3,24 +3,23 @@ .\" describe the actual OpenBSD implimentation. Permission for .\" use of this page comes from Rob Pike <rob@plan9.att.com>. .\" -.TH RFORK 2 -.SH NAME -rfork \- manipulate process resources -.SH SYNOPSIS -.B #include <sys/param.h> -.br -.B #include <unistd.h> -.PP -.nf -.B -int rfork(int flags) -.fi -.SH DESCRIPTION -Forking or rforking is the only way new processes are created. +.Dd Jan 12, 1996 +.Dt RFORK 2 +.Os +.Sh NAME +.Nm rfork +.Nd manipulate process resources +.Sh SYNOPSIS +.Fd #include <sys/param.h> +.Fd #include <unistd.h> +.Ft int +.Fn rfork "int flags" +.Sh DESCRIPTION +Forking, vforking or rforking is the only way new processes are created. The -.I flags +.Fa flags argument to -.I rfork +.Fn rfork selects which resources of the invoking process (parent) are shared by the new process (child) or initialized to @@ -29,73 +28,86 @@ The resources include the open file descriptor table (which, when shared, permits processes to open and close files for other processes), and open files. -.I Flags +.Fa Flags is the logical OR of some subset of -.TF RFCNAMEG -.TP -.B RFPROC +.Bl -tag -width "RFCNAMEG" -compact -offset indent +.It RFPROC If set a new process is created; otherwise changes affect the current process. The current implementation requires this flag to always be set. -.TP -.B RFNOWAIT +.It RFNOWAIT If set, the child process will be dissociated from the parent. Upon -exit the child will leave no -.B Waitmsg -(see -.IR wait (2)) -for the parent to collect. +exit the child will not leave a status for the parent to collect. +See +.Xr wait 2 . This is not currently implemented. -.TP -.B RFNAMEG, RFCNAMEG, RFENVG, RFCENVG, RFNOTEG +.It RFNAMEG, RFCNAMEG, RFENVG, RFCENVG, RFNOTEG These are Plan 9 specific flags, and not implimented. -.TP -.B RFFDG +.It RFFDG If set, the invoker's file descriptor table (see -.IR intro (2)) -is copied; otherwise the two processes share a +.Xr intro 2 +) is copied; otherwise the two processes share a single table. -.TP -.B RFCFDG +.It RFCFDG If set, the new process starts with a clean file descriptor table. Is mutually exclusive with -.BR RFFDG . -.TP -.B RFMEM +.Dv RFFDG . +.It RFMEM If set, the kernel will force sharing of the entire address 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 -.BR RFPROC . -.PD -.PP +.Dv RFPROC . +.El +.Pp File descriptors in a shared file descriptor table are kept open until either they are explicitly closed or all processes sharing the table exit. -.PP +.Pp If -.B RFPROC +.Dv 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. Without -.BR RFPROC , +.Dv RFPROC , the return value is zero. Process ids range from 1 to the maximum integer -.RB ( int ) +.Ft ( int ) value. -.I Rfork +.Fn Rfork will sleep, if necessary, until required process resources are available. -.PP -.I Fork +.Pp +.Fn Fork can be implemented as a call to -.BR rfork(RFFDG|RFPROC) +.Xr rfork "RFFDG|RFPROC" but isn't for backwards compatibility. -.SH SEE ALSO -.IR intro (2), -.IR fork (2), -.IR minherit (2). - +.Sh ERRORS +.Fn Rfork +will fail and no child process will be created if: +.Bl -tag -width Er +.It Bq Er EAGAIN +The system-imposed limit on the total +number of processes under execution would be exceeded. +This limit is configuration-dependent. +.It Bq Er EAGAIN +The system-imposed limit +.Dv MAXUPRC +.Pq Aq Pa sys/param.h +on the total number of +processes under execution by a single user would be exceeded. +.It Bq Er ENOMEM +There is insufficient swap space for the new process. +.El +.Sh SEE ALSO +.Xr intro 2 , +.Xr fork 2 , +.Xr vfork 2 , +.Xr minherit 2 +.Sh HISTORY +The +.Fn rfork +function first appeared in Plan9. |