Re: your mail

Erik Mouw
2001-05-17T00:19:22Z

On Wed, May 16, 2001 at 08:05:38AM -0700, siva prasad wrote:
> Is it true that the ipc calls like
> msgget(),shmget()...
> are not really system calls?

No, they all use a system call, but the system call is the same for all
functions.

> Cos in the file "asm/unistd.h" where the
> system calls are listed as __NR_xxx we dont find
> the appropriate listing for the ipc calls.
> What I guessed was that all the ipc calls are
> clubbed under the 'int ipc()' system call and this
> is well listed in the "asm/unistd.h"

Right, they all use __NR_ipc. See sys_ipc() in
arch/i386/kernel.sys_i386.c, especially the comment right above the
function...

> Could some one explain why the ipc is implemented
> this way rather that implementing them as individual
> system calls as in UNIX.

Probably because the original designer liked it this way and nobody
cared enough to do it otherwise.

> Or is it the same way in UNIX

I don't know, I don't have Unix source available.

Erik

--
J.A.K. (Erik) Mouw, Information and Communication Theory Group, Department
of Electrical Engineering, Faculty of Information Technology and Systems,
Delft University of Technology, PO BOX 5031, 2600 GA Delft, The Netherlands
Phone: +31-15-2783635 Fax: +31-15-2781843 Email: J.A.K.Mouw@its.tudelft.nl
WWW: http://www-ict.its.tudelft.nl/~erik/