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ipc(2) [centos man page]

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

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 Linux 2012-10-16 IPC(2)

Check Out this Related Man Page

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

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
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 GNU
2001-11-28 FTOK(3)

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