projects / apple / xnu.git / blame
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1 | .\" $Darwin$ |
| 2 | .\" | |
| 3 | .\" Copyright (c) 1999-2002 Apple Computer, Inc. All rights reserved. | |
| 4 | .\" | |
| 5 | .\" @APPLE_LICENSE_HEADER_START@ | |
| 6 | .\" | |
| 7 | .\" The contents of this file constitute Original Code as defined in and | |
| 8 | .\" are subject to the Apple Public Source License Version 1.1 (the | |
| 9 | .\" "License"). You may not use this file except in compliance with the | |
| 10 | .\" License. Please obtain a copy of the License at | |
| 11 | .\" http://www.apple.com/publicsource and read it before using this file. | |
| 12 | .\" | |
| 13 | .\" This Original Code and all software distributed under the License are | |
| 14 | .\" distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER | |
| 15 | .\" EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, | |
| 16 | .\" INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, | |
| 17 | .\" FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the | |
| 18 | .\" License for the specific language governing rights and limitations | |
| 19 | .\" under the License. | |
| 20 | .\" | |
| 21 | .\" @APPLE_LICENSE_HEADER_END@ | |
| 22 | .\" | |
| 23 | .Dd August 31, 2006 | |
| 24 | .Dt SHM_UNLINK 2 | |
| 25 | .Os Darwin | |
| 26 | .Sh NAME | |
| 27 | .Nm shm_unlink | |
| 28 | .Nd remove shared memory object | |
| 29 | .Sh SYNOPSIS | |
| 30 | .Fd #include <sys/mman.h> | |
| 31 | .Ft int | |
| 32 | .Fn shm_unlink "const char *name" | |
| 33 | .Sh DESCRIPTION | |
| 34 | The | |
| 35 | .Fn shm_unlink | |
| 36 | function disassociates the shared memory object specified by | |
| 37 | .Fa name | |
| 38 | from that name. | |
| 39 | The resources associated with the shared memory object remain intact | |
| 40 | until the last file descriptor reference is removed, e.g., by | |
| 41 | .Xr close 2 | |
| 42 | or | |
| 43 | .Xr munmap 2 , | |
| 44 | at which point the resources are reclaimed | |
| 45 | (if no references exist at the time of the call to | |
| 46 | .Fn shm_unlink , | |
| 47 | the resources are reclaimed immediately). | |
| 48 | The name can only be reused | |
| 49 | when it is bound to a new shared memory object with a call to | |
| 50 | .Xr shm_open 2 | |
| 51 | with the | |
| 52 | .Dv O_CREAT | |
| 53 | flag. | |
| 54 | .Sh RETURN VALUES | |
| 55 | Upon successful completion, a value of 0 is returned. | |
| 56 | Otherwise, a value of -1 is returned and | |
| 57 | .Va errno | |
| 58 | is set to indicate the error, | |
| 59 | and the named shared memory object will remain unchanged. | |
| 60 | .Sh ERRORS | |
| 61 | The | |
| 62 | .Fn shm_unlink | |
| 63 | succeeds unless: | |
| 64 | .Bl -tag -width Er | |
| 65 | .It Bq Er EACCES | |
| 66 | Permission is denied to be remove the object. | |
| 67 | .It Bq Er ENAMETOOLONG | |
| 68 | .Fa name | |
| 69 | exceeded the name size limit. | |
| 70 | This is currently | |
| 71 | .Dv PSHMNAMLEN | |
| 72 | characters (defined in | |
| 73 | .In sys/posix_shm.h ) , | |
| 74 | but this may change in the future. | |
| 75 | .It Bq Er ENOENT | |
| 76 | The named object does not exist. | |
| 77 | .El | |
| 78 | .Sh SEE ALSO | |
| 79 | .Xr close 2 , | |
| 80 | .Xr mmap 2 , | |
| 81 | .Xr munmap 2 , | |
| 82 | .Xr shm_open 2 , | |
| 83 | .Xr shmat 2 , | |
| 84 | .Xr shmctl 2 | |
| 85 | .Sh HISTORY | |
| 86 | .Fn shm_open | |
| 87 | is specified in the POSIX Realtime Extension (1003.1b-1993/1003.1i-1995). |