Hi folks...

I have just added new positional I/O system calls, per XPG4.2, pread(2)
and pwrite(2).  These are like read(2) and write(2) except they also
take an absolute offset at which to begin the I/O.  They do not modify
the file pointer.

I also added preadv(2) and pwritev(2), like readv(2) and writev(2), but
also taking a positional argument.

SVR4 has had these for a while, and database applications like to use
them because they eliminate 50% of the system calls for completely
random access to a file.

I'm going to change some of NetBSD's code to use the new system calls
later today so that people will have some example usage, in addition
to the manual page.

Enjoy!

Jason R. Thorpe                                       thorpej@nas.nasa.gov
NASA Ames Research Center                            Home: +1 408 866 1912
NAS: M/S 258-5                                       Work: +1 650 604 0935
Moffett Field, CA 94035                             Pager: +1 650 428 6939