87 lines
2.4 KiB
Groff
87 lines
2.4 KiB
Groff
.\" $Darwin$
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.\"
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.\" Copyright (c) 1999-2002 Apple Computer, Inc. All rights reserved.
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.\"
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.\" @APPLE_LICENSE_HEADER_START@
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.\"
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.\" The contents of this file constitute Original Code as defined in and
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.\" are subject to the Apple Public Source License Version 1.1 (the
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.\" "License"). You may not use this file except in compliance with the
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.\" License. Please obtain a copy of the License at
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.\" http://www.apple.com/publicsource and read it before using this file.
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.\"
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.\" This Original Code and all software distributed under the License are
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.\" distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
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.\" EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
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.\" INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
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.\" FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the
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.\" License for the specific language governing rights and limitations
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.\" under the License.
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.\"
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.\" @APPLE_LICENSE_HEADER_END@
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.\"
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.Dd August 31, 2006
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.Dt SHM_UNLINK 2
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.Os Darwin
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.Sh NAME
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.Nm shm_unlink
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.Nd remove shared memory object
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.Sh SYNOPSIS
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.Fd #include <sys/mman.h>
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.Ft int
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.Fn shm_unlink "const char *name"
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.Sh DESCRIPTION
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The
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.Fn shm_unlink
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function disassociates the shared memory object specified by
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.Fa name
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from that name.
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The resources associated with the shared memory object remain intact
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until the last file descriptor reference is removed, e.g., by
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.Xr close 2
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or
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.Xr munmap 2 ,
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at which point the resources are reclaimed
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(if no references exist at the time of the call to
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.Fn shm_unlink ,
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the resources are reclaimed immediately).
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The name can only be reused
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when it is bound to a new shared memory object with a call to
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.Xr shm_open 2
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with the
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.Dv O_CREAT
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flag.
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.Sh RETURN VALUES
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Upon successful completion, a value of 0 is returned.
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Otherwise, a value of -1 is returned and
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.Va errno
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is set to indicate the error,
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and the named shared memory object will remain unchanged.
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.Sh ERRORS
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The
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.Fn shm_unlink
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succeeds unless:
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.Bl -tag -width Er
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.It Bq Er EACCES
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Permission is denied to be remove the object.
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.It Bq Er ENAMETOOLONG
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.Fa name
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exceeded the name size limit.
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This is currently
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.Dv PSHMNAMLEN
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characters (defined in
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.In sys/posix_shm.h ) ,
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but this may change in the future.
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.It Bq Er ENOENT
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The named object does not exist.
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.El
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.Sh SEE ALSO
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.Xr close 2 ,
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.Xr mmap 2 ,
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.Xr munmap 2 ,
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.Xr shm_open 2 ,
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.Xr shmat 2 ,
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.Xr shmctl 2
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.Sh HISTORY
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.Fn shm_open
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is specified in the POSIX Realtime Extension (1003.1b-1993/1003.1i-1995).
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