03-25-2010
the clients terminal device must cause the 'server' process to register it within the server process and initialize a shared memory segment. I don't see the need for mutexing as the shared memory segment is being modified by only one process and read by only process also. Hence no corrupt data can occur. I was hoping to implement this without the use of sockets.
9 More Discussions You Might Find Interesting
1. UNIX for Advanced & Expert Users
Dear Members,
I have aquired a load of old Wyse dumb terminals. I have a Linux system set up that I want to be the host for all of these. Now, I know these don't use cat5 or standard networking. They are all done through serial (com) ports. However, I researched this more and found a converter... (25 Replies)
Discussion started by: Phobos
25 Replies
2. UNIX for Advanced & Expert Users
Dear All,
I have two files, which looks like:
File 1
124
235
152
178
156
142
178
163
159
File 2
124|5623
452|6698
178|9995 (8 Replies)
Discussion started by: rochitsharma
8 Replies
3. Shell Programming and Scripting
I'd like to write a script that will call n number of terminals that will all ssh to X-server and automatically enter the same password.
Unfortunately I'm not exactly sure what kind of commands would work for me here because when I call for gnome-terminal, a new terminal pops up and the old... (1 Reply)
Discussion started by: gelitini
1 Replies
4. Shell Programming and Scripting
Hi, I'm looking for a way to send commands through multiple shells/terminals (not sure which is proper syntax). Basically, I have to open 3 different shells/terminals and run separate parts of a program suite in each of them. I find this annoying. The commands I have to do are simple, and could... (1 Reply)
Discussion started by: Caradoc
1 Replies
5. AIX
I just wondering if there are ways to open multiple virtual terminal to a single LPAR.
After I have use putty to login to the VIOS. I will use mkvt -id <LPAR id> to open console but if my friend want to open 2 second one, it will say, VT already connected.
IS there a way to work this around ? ... (1 Reply)
Discussion started by: wingcross
1 Replies
6. Shell Programming and Scripting
Hi i have written a shell script that takes only single ip address from the user and calculates its latency and reliability, can you please tell me that what should be done if i want that user should enter 100 or 1000 ip address (5 Replies)
Discussion started by: Preeti_17
5 Replies
7. Shell Programming and Scripting
Dear all,
My work is completely stuck cos of the following issue. Please find it here and kindly help me.
Task is following:
I have set of files with such pattern
1t-rw-rw-r-- 1 emily emily 119 Jun 11 10:45 vgtree_5_1_pfs.root
3t-rw-rw-r-- 1 emily emily 145 Jun 11 10:46 vgtree_5_3_pfs.root... (4 Replies)
Discussion started by: emily
4 Replies
8. Shell Programming and Scripting
Hi
I am new to Ubuntu and Bash scripting. I am working on a project to give a demo on an SDN application to my class. I need some help in scripting to create the demo. Please help in case if you have any idea on what am asking.
The demo uses a tool called mininet. I need just one script so... (2 Replies)
Discussion started by: anzal
2 Replies
9. Shell Programming and Scripting
Hi Guys,
I have created a script for our automated DB creation, it works fine with default option(-d).
$ ./test_db.ksh -d abc 11 dev
-d is Default option
ORACLE_SID=abc
ORACLE_VERSION=11
ENV_TYPE=dev
For creating a customized DB, i thought of giving the user different options.... (8 Replies)
Discussion started by: veeresh_15
8 Replies
SHMAT(2) BSD System Calls Manual SHMAT(2)
NAME
shmat, shmdt -- map/unmap shared memory
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <sys/shm.h>
void *
shmat(int shmid, const void *shmaddr, int shmflg);
int
shmdt(const void *shmaddr);
DESCRIPTION
shmat() maps the shared memory segment associated with the shared memory identifier shmid into the address space of the calling process. The
address at which the segment is mapped is determined by the shmaddr parameter. If it is equal to 0, the system will pick an address itself.
Otherwise, an attempt is made to map the shared memory segment at the address shmaddr specifies. If SHM_RND is set in shmflg, the system
will round the address down to a multiple of SHMLBA bytes (SHMLBA is defined in <sys/shm.h>).
A shared memory segment can be mapped read-only by specifying the SHM_RDONLY flag in shmflg.
shmdt() unmaps the shared memory segment that is currently mapped at shmaddr from the calling process' address space. shmaddr must be a
value returned by a prior shmat() call. A shared memory segment will remain in existence until it is removed by a call to shmctl(2) with the
IPC_RMID command.
RETURN VALUES
shmat() returns the address at which the shared memory segment has been mapped into the calling process' address space when successful,
shmdt() returns 0 on successful completion. Otherwise, a value of -1 is returned, and the global variable errno is set to indicate the
error.
ERRORS
shmat() will fail if:
[EACCES] The calling process has no permission to access this shared memory segment.
[ENOMEM] There is not enough available data space for the calling process to map the shared memory segment.
[EINVAL] shmid is not a valid shared memory identifier.
shmaddr specifies an illegal address.
[EMFILE] The number of shared memory segments has reached the system-wide limit.
shmdt() will fail if:
[EINVAL] shmaddr is not the start address of a mapped shared memory segment.
SEE ALSO
ipcrm(1), ipcs(1), mmap(2), shmctl(2), shmget(2)
STANDARDS
The shmat and shmdt system calls conform to X/Open System Interfaces and Headers Issue 5 (``XSH5'').
HISTORY
Shared memory segments appeared in the first release of AT&T System V UNIX.
BSD
June 17, 2002 BSD