Based on my google this, it is shared memory. What is this shared memory and where exactly it is used? Can you please help me to understand more about this?
Last edited by pludi; 03-17-2010 at 03:04 AM..
Reason: code tags, please...
I am running HP-UX B.11.11.
I'm increasing a parameter for a database engine so that it uses more memory to buffer the disk drive (to speed up performance). I have over 5GB of memory not being used.
But when I try to start the DB with the increased buffer parameter I get told.
"Not... (1 Reply)
hi,
this is the problem: i want to swap a linked list between 4 processes (unrelated), is there any way i can do that just by sending a pointer to a structure?
//example
typedef struct node
{
int x;
char c;
struct node *next;
} node;
or i should send the items ( x,c ) by... (9 Replies)
I need to create a shared library to access an in memory DB. The DB is not huge, but big enough to make it cumbersome to carry around in every single process using the shared library. Luckily, it is pretty static information, so I don't need to worry much about synchronizing the data between... (12 Replies)
I am writing a shared library in Linux (but compatible with other UNIXes) and I want to allow multiple instances to share a piece of memory -- 1 byte is enough. What's the "best" way to do this? I want to optimize for speed and portability.
Obviously, I'll have to worry about mutual exclusion. (0 Replies)
Dear Friends ,
I am confused about shared memory in Linux . plz look @ the below output :
$ df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda1 126G 61G 59G 52% /
tmpfs 1.7G 0 1.7G 0% /dev/shm
Here , I see that every time... (1 Reply)
Hello.
I am new to this forum and I would like to ask for advice about low level POSIX programming.
I have to implement a POSIX compliant C shared library.
A file will have some variables and the shared library will have some functions which need those variables.
There is one special... (5 Replies)
So I am pretty new to the linux environment, and I am trying to create a shell that uses multiple pipes, and I read online that piping using shared memory space is more efficient than using regular piping. However, I have zero clue how to use shared memory space with pipes. Has anyone done this... (1 Reply)
Discussion started by: Greg_MC
1 Replies
LEARN ABOUT OPENSOLARIS
shm
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)