Linux and UNIX Man Pages

Linux & Unix Commands - Search Man Pages

ipc(2) [centos man page]

IPC(2)							     Linux Programmer's Manual							    IPC(2)

NAME
ipc - System V IPC system calls SYNOPSIS
int ipc(unsigned int call, int first, int second, int third, void *ptr, long fifth); DESCRIPTION
ipc() is a common kernel entry point for the System V IPC calls for messages, semaphores, and shared memory. call determines which IPC function to invoke; the other arguments are passed through to the appropriate call. User programs should call the appropriate functions by their usual names. Only standard library implementors and kernel hackers need to know about ipc(). CONFORMING TO
ipc() is Linux-specific, and should not be used in programs intended to be portable. NOTES
On some architectures--for example x86-64 and ARM--there is no ipc() system call; instead msgctl(2), semctl(2), shmctl(2), and so on really are implemented as separate system calls. SEE ALSO
msgctl(2), msgget(2), msgrcv(2), msgsnd(2), semctl(2), semget(2), semop(2), semtimedop(2), shmat(2), shmctl(2), shmdt(2), shmget(2) COLOPHON
This page is part of release 3.53 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/. Linux 2012-10-16 IPC(2)

Check Out this Related Man Page

FTOK(3) 						     Linux Programmer's Manual							   FTOK(3)

NAME
ftok - convert a pathname and a project identifier to a System V IPC key SYNOPSIS
#include <sys/types.h> #include <sys/ipc.h> key_t ftok(const char *pathname, int proj_id); DESCRIPTION
The ftok() function uses the identity of the file named by the given pathname (which must refer to an existing, accessible file) and the least significant 8 bits of proj_id (which must be nonzero) to generate a key_t type System V IPC key, suitable for use with msgget(2), semget(2), or shmget(2). The resulting value is the same for all pathnames that name the same file, when the same value of proj_id is used. The value returned should be different when the (simultaneously existing) files or the project IDs differ. RETURN VALUE
On success, the generated key_t value is returned. On failure -1 is returned, with errno indicating the error as for the stat(2) system call. CONFORMING TO
POSIX.1-2001. NOTES
Under libc4 and libc5 (and under SunOS 4.x) the prototype was: key_t ftok(char *pathname, char proj_id); Today proj_id is an int, but still only 8 bits are used. Typical usage has an ASCII character proj_id, that is why the behavior is said to be undefined when proj_id is zero. Of course no guarantee can be given that the resulting key_t is unique. Typically, a best effort attempt combines the given proj_id byte, the lower 16 bits of the inode number, and the lower 8 bits of the device number into a 32-bit result. Collisions may easily happen, for example between files on /dev/hda1 and files on /dev/sda1. SEE ALSO
msgget(2), semget(2), shmget(2), stat(2), svipc(7) COLOPHON
This page is part of release 3.44 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/. GNU
2001-11-28 FTOK(3)

15 More Discussions You Might Find Interesting

1. Programming

Inter Process Communication

unix IPC i would like to know the method of usage of semaphores on shared memory segments the topic seems very difficult to understand mainly when difrent proceses communicate instantly and how do i avaoid deadlock situation (2 Replies)
Discussion started by: kamathanil
2 Replies

2. UNIX for Dummies Questions & Answers

SUN IPC Workstation Q

I know that there are lots of UNIX pros here so I'm asking for some help. I have recently acquired 2 SUN IPC Workstations. The stations were destined for the garbage so I was unable to talk to the owners. Neither of them will make it through the boot process. One gives an error "le0: No... (2 Replies)
Discussion started by: shaggy
2 Replies

3. Programming

semclt system call ???

hi mates, What is the : semctl system call for? any example will be helpful and be appreciated. cya and thanx abdul (2 Replies)
Discussion started by: abdul
2 Replies

4. Programming

Unix/Linux Newbie(ish) Question - IPC/Signals

:) Hello, i have been given the following code to help me learn how to use signals, it won't compile. The problem maybe because this was written for use in Unix and i am trying to compile in Linux. The error i get says that SIGPIPE and SIG_IGN are undeclared. I think that these are defined... (2 Replies)
Discussion started by: theultimatechuf
2 Replies

5. Programming

OpenVMS IPC and TCP/IP Programming

We have a requirement to port applications from Unix to HP Vax OpenVMS Server. For this I need to self-educate on various IPC and networking APIs available in OpenVMS. I goggled a lot but could not find of how to implement Semaphores, Message Queues and all other forms of IPC available in Unix... (7 Replies)
Discussion started by: S.P.Prasad
7 Replies

6. UNIX for Dummies Questions & Answers

Data Transfer programs in IPC Mechanisms??

I have no IPC Mechanisms program which includes data transfer on the same Linu machine. All mechanisms of IPC must be tested. If anyone have programs about it, could you send to me?? I am waiting your answers. please help me...!!!! (2 Replies)
Discussion started by: boris35
2 Replies

7. UNIX for Dummies Questions & Answers

Ipc Details

hai, i am doing my masters degree in computers.please any one tell me about fork(),semaphores,mutex,messaging queues,messaging using pipes ,and msgget(),msgrecv() funtions in ipc programming . i have exam on that i have a book but in that they not given clearly. hope u will ... (2 Replies)
Discussion started by: G.Vishnuvardhan
2 Replies

8. Programming

Compilation problem with semtimedop

Hi, I'm porting code from Windows to HP-UX 11, compiling with gcc. I have a call to semtimedop with 4 arguments as in the definition: int semtimedop(int, struct sembuf *, unsigned int, const struct timespec *); When compiling I get an error saying: error: 'semtimedop' was not declared in... (3 Replies)
Discussion started by: rimon
3 Replies

9. UNIX for Advanced & Expert Users

Possible to link an IPC Sempahore to a process ID?

Hi, Anyone knows whether it is possible to link/relate an IPC semaphore to a particular process ID? e.g. # ipcs -as IPC status from <running system> as of Wednesday July 2 14:10:39 EST 2008 T ID KEY MODE OWNER GROUP CREATOR CGROUP NSEMS OTIME CTIME... (8 Replies)
Discussion started by: Solarius
8 Replies

10. UNIX for Dummies Questions & Answers

Interprocess Communication

Hiya Everybody just joined, Not sure if this is the right section:o I require abit of an assistance with IPC! I know there are different types of IPC porcesses like signals, semaphores, mutexes, shared memory, message queues, pipes and sockets. Now say a system has a number of... (4 Replies)
Discussion started by: G.I.Joe
4 Replies

11. Infrastructure Monitoring

Database table and Shared mem Sync issues

Hi, I wanted ideas on how to achieve this efficiently using C++ concept:- I have a DB table that contains rows of endpoints (say IDs vs names). There is process say "A" that calls another process B's API to increment counters if an operation is performed by an endpoint. DB table:- ID ... (3 Replies)
Discussion started by: trendzy2010
3 Replies

12. Shell Programming and Scripting

An alternative to IPC mechanism

What if the operating systems would not use any ipc mechanism in order to exchange the datas with each other,which technique could be an alternative for messaging between the processes?Do you guys think using the vfork () system call to duplicate processes is a logical solution for this problem? (4 Replies)
Discussion started by: helltrex
4 Replies

13. Programming

IPC Mechanisms

Hi! I wanted to know the advantages / disadvantages of different IPC mechanims such as sockets, pipes (unnamed) , shared memory & message queues. Pipes for example i hear are fast , but are difficult to debug as compared to sockets. Can you guys please name some situations where one is... (4 Replies)
Discussion started by: _korg
4 Replies

14. UNIX for Advanced & Expert Users

Chat program between two soft terminals of my Linux machine

here i havent tried to make a communication between two terminals of different machines not either any socket program my simple aim is use ipc for chat between two soft terminals(tty's) here is my view two terminals with two applications working on same fifo one fifo b/w two terminals try... (3 Replies)
Discussion started by: shyam.sunder91
3 Replies

15. Programming

Msgget(2) returns 0 - a workaround fix

Greetings: I am posting this because my searches for this problem only came up with two posts and no helpful suggestions. I have a "solution" (read work-around hack) and have not tried yet to find a root cause, and may never because I am busy doing other things (read working to pay the bills). ... (10 Replies)
Discussion started by: mr_bandit
10 Replies

Featured Tech Videos