05-30-2013
Is swap and Shared memory the same ?
In Linux, Unix environments Is swap and Shared memory the same ?
In Linux, swap is mounted on /dev/shm ? I am wondering if the naming of 'shm' has anything to do with Shared memory ?
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LEARN ABOUT OPENSOLARIS
shm.h
shm.h(3HEAD) Headers shm.h(3HEAD)
NAME
shm.h, shm - shared memory facility
SYNOPSIS
#include <sys/shm.h>
DESCRIPTION
The <sys/shm.h> header defines the following symbolic constants:
SHM_RDONLY attach read-only (else read-write)
SHM_RND round attach address to SHMLBA
The <sys/shm.h> header defines the following symbolic value:
SHMLBA segment low boundary address multiple
The following data types are defined through typedef:
shmatt_t Unsigned integer used for the number of current attaches that must be able to store values at least as large as a type unsigned
short.
The shmid_ds structure contains the following members:
struct ipc_perm shm_perm /* operation permission structure */
size_t shm_segsz /* size of segment in bytes */
pid_t shm_lpid /* process ID of last shared memory
operation */
pid_t shm_cpid /* process ID of creator */
shmatt_t shm_nattch /* number of current attaches */
time_t shm_atime /* time of last shmat() */
time_t shm_dtime /* time of last shmdt() */
time_t shm_ctime /* time of last change by shmctl() */
The pid_t, time_t, key_t, and size_t types are defined as described in <sys/types.h>. See types.h(3HEAD).
In addition, all of the symbols from <sys/ipc.h> are defined when this header is included.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Interface Stability |Standard |
+-----------------------------+-----------------------------+
SEE ALSO
shmctl(2), shmget(2), shmop(2), ipc.h(3HEAD), types.h(3HEAD), attributes(5), standards(5)
SunOS 5.11 10 Sep 2004 shm.h(3HEAD)