diff options
Diffstat (limited to 'man2/shmctl.2')
| -rw-r--r-- | man2/shmctl.2 | 60 |
1 files changed, 14 insertions, 46 deletions
diff --git a/man2/shmctl.2 b/man2/shmctl.2 index 678982a6f3..4301f5df8c 100644 --- a/man2/shmctl.2 +++ b/man2/shmctl.2 @@ -1,11 +1,7 @@ .\" Copyright (c) 1993 Luigi P. Bai (lpb@softint.com) July 28, 1993 .\" May be distributed under the GNU General Public License. .\" Modified Wed Jul 28 11:03:24 1993, Rik Faith (faith@cs.unc.edu) -.\" Modified Sun Nov 28 16:43:30 1993, Rik Faith (faith@cs.unc.edu) -.\" with material from Giorgio Ciucci (giorgio@crcc.it) -.\" Portions Copyright 1993 Giorgio Ciucci (giorgio@crcc.it) -.\" May be distributed under the GNU General Public License. -.TH SHMCTL 2 "November 28, 1993" "Linux 0.99.11" "Linux Programmer's Manual" +.TH SHMCTL 2 "July 28, 1993" "Linux 0.99.11" "Linux Programmer's Manual" .SH NAME shmctl \- shared memory control .SH SYNOPSIS @@ -61,27 +57,21 @@ struct ipc_perm .PP The following \fIcmds\fP are available: .br -.TP 12 +.TP 0.8i .B IPC_STAT is used to copy the information about the shared memory segment into the buffer \fIbuf\fP. The user must have \fBread\fP access to the shared memory segment. .TP .B IPC_SET -is used to apply the changes the user has made to the \fIuid\fP, \fIgid\fP, -or \fImode\fP members of the \fIshm_perms\fP field. Only the lowest 9 bits -of \fImode\fP are used. The -.I shm_ctime -member is also updated. The user must be the owner, creator, or the -super-user. +is used to apply the changes the user has made to the +\fIuid\fP, \fIgid\fP, or \fImode\fP members of the \fIshm_perms\fP field. +The user must be the owner, creator, or the super-user. .TP .B IPC_RMID is used to mark the segment as destroyed. It will actually be destroyed -after the last detach. (I.e., when the -.I shm_nattch -member of the associated structure -.I shmid_ds -is zero.) The user must be the owner, creator, or the super-user. +after the last detach. +The user must be the owner, creator, or the super-user. .PP The user \fImust\fP ensure that a segment is eventually destroyed; otherwise its pages that were faulted in will remain in memory or swap. @@ -89,7 +79,7 @@ its pages that were faulted in will remain in memory or swap. In addition, the \fBsuper-user\fP can prevent or allow swapping of a shared memory segment with the following \fIcmds\fP: (Linux only) .br -.TP 12 +.TP 0.8i .B SHM_LOCK prevents swapping of a shared memory segment. The user must fault in any pages that are required to be present after locking is enabled. @@ -97,17 +87,7 @@ any pages that are required to be present after locking is enabled. .B SHM_UNLOCK allows the shared memory segment to be swapped out. .PP -The -.BR IPC_INFO , -.BR SHM_STAT -and -.B SHM_INFO -control calls are used by the -.BR ipcs (1) -program to provide information on allocated resources. In the future, -these man be modified as needed or moved to a proc file system interface. -.PP -.SH "SYSTEM CALLS" +.SH SYSTEM CALLS .TP .B fork() After a @@ -125,27 +105,15 @@ Upon all attached shared memory segments are detached (not destroyed). .PP .SH "RETURN VALUE" -0 is returned on success, \-1 on error. +0 is returned on success, -1 on error. .SH ERRORS -On error, -.B errno -will be set to one of the following: -.TP 12 +.TP 0.8i .B EACCESS is returned if \fBIPC_STAT\fP is requested and -\fIshm_perm.modes\fP does not allow read access for -.IR msqid . +\fIshm_perm.modes\fP does not allow read access. .TP .B EFAULT -The argument -.I cmd -has value -.B IPC_SET -or -.B IPC_STAT -but the address pointed to by -.I buf -isn't accessible. +is returned if \fIbuf\fP is not accessible. .TP .B EINVAL is returned if \fIshmid\fP is not a valid identifier, or \fIcmd\fP @@ -158,5 +126,5 @@ is returned if \fIshmid\fP points to a removed identifier. is returned if \fBIPC_SET\fP or \fBIPC_RMID\fP is attempted, and the user is not the creator, the owner, or the super-user, and the user does not have permission granted to their group or to the world. -.SH "SEE ALSO" +.SH SEE ALSO .BR shmget "(2), " shmop (2) |