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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-24 04:52:22 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-24 04:52:22 +0000 |
commit | 3d08cd331c1adcf0d917392f7e527b3f00511748 (patch) | |
tree | 312f0d1e1632f48862f044b8bb87e602dcffb5f9 /man7/shm_overview.7 | |
parent | Adding debian version 6.7-2. (diff) | |
download | manpages-3d08cd331c1adcf0d917392f7e527b3f00511748.tar.xz manpages-3d08cd331c1adcf0d917392f7e527b3f00511748.zip |
Merging upstream version 6.8.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'man7/shm_overview.7')
-rw-r--r-- | man7/shm_overview.7 | 104 |
1 files changed, 0 insertions, 104 deletions
diff --git a/man7/shm_overview.7 b/man7/shm_overview.7 deleted file mode 100644 index a049e4c..0000000 --- a/man7/shm_overview.7 +++ /dev/null @@ -1,104 +0,0 @@ -.\" Copyright (C) 2008, Linux Foundation, written by Michael Kerrisk -.\" <mtk.manpages@gmail.com> -.\" -.\" SPDX-License-Identifier: Linux-man-pages-copyleft -.\" -.TH shm_overview 7 2023-10-31 "Linux man-pages 6.7" -.SH NAME -shm_overview \- overview of POSIX shared memory -.SH DESCRIPTION -The POSIX shared memory API allows processes to communicate information -by sharing a region of memory. -.P -The interfaces employed in the API are: -.TP 15 -.BR shm_open (3) -Create and open a new object, or open an existing object. -This is analogous to -.BR open (2). -The call returns a file descriptor for use by the other -interfaces listed below. -.TP -.BR ftruncate (2) -Set the size of the shared memory object. -(A newly created shared memory object has a length of zero.) -.TP -.BR mmap (2) -Map the shared memory object into the virtual address space -of the calling process. -.TP -.BR munmap (2) -Unmap the shared memory object from the virtual address space -of the calling process. -.TP -.BR shm_unlink (3) -Remove a shared memory object name. -.TP -.BR close (2) -Close the file descriptor allocated by -.BR shm_open (3) -when it is no longer needed. -.TP -.BR fstat (2) -Obtain a -.I stat -structure that describes the shared memory object. -Among the information returned by this call are the object's -size -.RI ( st_size ), -permissions -.RI ( st_mode ), -owner -.RI ( st_uid ), -and group -.RI ( st_gid ). -.TP -.BR fchown (2) -To change the ownership of a shared memory object. -.TP -.BR fchmod (2) -To change the permissions of a shared memory object. -.SS Versions -POSIX shared memory is supported since Linux 2.4 and glibc 2.2. -.SS Persistence -POSIX shared memory objects have kernel persistence: -a shared memory object will exist until the system is shut down, -or until all processes have unmapped the object and it has been deleted with -.BR shm_unlink (3) -.SS Linking -Programs using the POSIX shared memory API must be compiled with -.I cc \-lrt -to link against the real-time library, -.IR librt . -.SS Accessing shared memory objects via the filesystem -On Linux, shared memory objects are created in a -.RB ( tmpfs (5)) -virtual filesystem, normally mounted under -.IR /dev/shm . -Since Linux 2.6.19, Linux supports the use of access control lists (ACLs) -to control the permissions of objects in the virtual filesystem. -.SH NOTES -Typically, processes must synchronize their access to a shared -memory object, using, for example, POSIX semaphores. -.P -System V shared memory -.RB ( shmget (2), -.BR shmop (2), -etc.) is an older shared memory API. -POSIX shared memory provides a simpler, and better designed interface; -on the other hand POSIX shared memory is somewhat less widely available -(especially on older systems) than System V shared memory. -.SH SEE ALSO -.BR fchmod (2), -.BR fchown (2), -.BR fstat (2), -.BR ftruncate (2), -.BR memfd_create (2), -.BR mmap (2), -.BR mprotect (2), -.BR munmap (2), -.BR shmget (2), -.BR shmop (2), -.BR shm_open (3), -.BR shm_unlink (3), -.BR sem_overview (7) |