all about shared memory

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1. Programming

Shared library with acces to shared memory.

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...

2. AIX

shared memory

1.How to know wich process is using the shared memory? 2.How to flush (release) the process from the shared memory?

3. UNIX for Advanced & Expert Users

Shared Memory

Hi, Using ipcs we can see shared memory, etc.. details. How can I add/remove shared memory(command name)? Thanks, Naga:cool:

4. Programming

Shared memory for shared library

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.

5. Programming

Shared memory in shared library

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...

6. Programming

memory sharing - not shared memory -

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...

7. Programming

help with shared memory

what i want to do is have an int that can been written into by 2 processes but my code doesn't seem to work. #include <sys/types.h> #include <sys/ipc.h> #include <sys/sem.h> #include <sys/shm.h> #include<stdio.h> #define KEY1 (1492) int main() { int shmid; volatile int * addr;...

8. Programming

implement shared memory

hi all I have been asked to implement shared memory in user mode?But :rolleyes: im not understanding how to do this.And what does it mean in user mode?Is it that we need to simulate what kernal does...like attaching ,detaching memory..etc...? And would also like to know why shared memory is...

9. UNIX for Advanced & Expert Users

Shared memory shortage but lots of unused memory

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...

10. Programming

Shared memory

Dear Reader, Is is necessary to attach / dettach the shared memory segments for write operations , if more than one program is accessing same shared memory segments.. I have used semaphore mutex and still I'm getting segmentation fault when I write to the segment when other program is already...

LEARN ABOUT ULTRIX

ipcmk

IPCMK(1)							   User Commands							  IPCMK(1)

NAME

       ipcmk - make various IPC resources

SYNOPSIS

       ipcmk [options]

DESCRIPTION

       ipcmk allows you to create shared memory segments, message queues, and semaphore arrays.

OPTIONS

       Resources can be specified with these options:

       -M, --shmem size
	      Create  a  shared  memory  segment of size bytes.  The size argument may be followed by the multiplicative suffixes KiB (=1024), MiB
	      (=1024*1024), and so on for GiB, etc. (the "iB" is optional, e.g., "K" has the same meaning as "KiB") or the suffixes KB (=1000), MB
	      (=1000*1000), and so on for GB, etc.

       -Q, --queue
	      Create a message queue.

       -S, --semaphore number
	      Create a semaphore array with number of elements.

       Other options are:

       -p, --mode mode
	      Access permissions for the resource.  Default is 0644.

       -V, --version
	      Display version information and exit.

       -h, --help
	      Display help text and exit.

SEE ALSO

       ipcrm(1), ipcs(1)

AUTHOR

       Hayden A. James <hayden.james@gmail.com>

AVAILABILITY

       The  ipcmk  command  is	part  of the util-linux package and is available from Linux Kernel Archive <https://www.kernel.org/pub/linux/utils
       /util-linux/>.

util-linux							     July 2014								  IPCMK(1)

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