10 More Discussions You Might Find Interesting
1. Programming
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)
Discussion started by: iamjag
5 Replies
2. AIX
1.How to know wich process is using the shared memory?
2.How to flush (release) the process from the shared memory? (1 Reply)
Discussion started by: pchangba
1 Replies
3. UNIX for Advanced & Expert Users
Hi,
Using ipcs we can see shared memory, etc.. details. How can I add/remove shared memory(command name)?
Thanks,
Naga:cool: (2 Replies)
Discussion started by: Nagapandi
2 Replies
4. Programming
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)
Discussion started by: otheus
0 Replies
5. Programming
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)
Discussion started by: DreamWarrior
12 Replies
6. Programming
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)
Discussion started by: elzalem
9 Replies
7. Programming
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;... (6 Replies)
Discussion started by: ddx08
6 Replies
8. Linux
Hi all :confused: ,
I am new to unix.I have been asked to implement shared memory in user's mode.What does this mean?What is the difference it makes in kernel mode and in users mode?What are the advantages of this impemenation(user's mode)?
And also i would like to know why exactly shared... (0 Replies)
Discussion started by: vijaya2006
0 Replies
9. UNIX for Advanced & Expert Users
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)
Discussion started by: cjcamaro
1 Replies
10. Programming
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... (1 Reply)
Discussion started by: joseph_shibu
1 Replies
shm_unlink(3) Library Functions Manual shm_unlink(3)
NAME
shm_unlink - Removes a shared memory object created by a call to the shm_open function (P1003.1b)
LIBRARY
Realtime Library (librt.so, librt.a)
SYNOPSIS
#include <sys/mman.h>
int shm_unlink (
const char *name);
PARAMETERS
*name Points to the name of the shared memory object.
DESCRIPTION
The shm_unlink function removes the name of the shared memory object pointed to by name. If this file descriptor is used by other func-
tions, all references to the shared memory object are removed, but content removal is delayed until all open and mapped references to the
shared memory object are removed.
RETURN VALUES
On a successful call to the shm_unlink function, a value of 0 (zero) is returned. Otherwise, a value of -1 is returned and errno is set to
indicate the error.
ERRORS
The shm_unlink function fails under the following conditions:
[EACCES] Permission to unlink the shared memory object is denied.
[ENAMETOOLONG] The length of the name argument exceeds PATH_MAX, or a pathname component is longer than NAME_MAX while _POSIX_NO_TRUNC
is in effect.
[ENOENT] The named shared memory object does not exist.
RELATED INFORMATION
Functions: close(2), mmap(2), munmap(2), shm_open(3)
Guide to Realtime Programming delim off
shm_unlink(3)