Installation guide

C
Differences Between DIGITAL UNIX and
ULTRIX System Calls
This appendix describes the differences between DIGITAL UNIX system
calls and ULTRIX system calls.
To use the table in this appendix, look for the name of an ULTRIX system
call in the left-hand column of the table. Read the second column of the
table to determine what difference exists between the DIGITAL UNIX and
ULTRIX system call. Read the right-hand column to determine how to get
the effect of the ULTRIX system call on a DIGITAL UNIX system.
ULTRIX
System Call
Difference from ULTRIX Systems Using on DIGITAL UNIX
Systems
getrusage
The structure returned in the
rusage parameter is different on
DIGITAL UNIX systems from the
structure returned on ULTRIX
systems. The ULTRIX structure
contains a field (ru_ismrss) that
the DIGITAL UNIX structure
does not contain.
Modify your application to use
the DIGITAL UNIX structure,
rather than the ULTRIX
structure. (The structure is
defined in the resource.h file.)
open
The O_FSYNC flag is not
supported.
Use the O_SYNC flag.
shmctl
The SHM_LOCK and
SHM_UNLOCK commands are
not supported.
Use the F_GETLCK and
F_SETLCK requests to the
fcntl call. See
fcntl(2) for
more information about these
requests.
setsockopt
The
optval and optlen
parameters are not optional; that
is, they cannot be specified as
zero (0).
Pass the appropriate parameters
for optval and optlen .
startcpu
Not on DIGITAL UNIX systems. No equivalent use.
stopcpu
Not on DIGITAL UNIX systems. No equivalent use.
vfork
Makes a copy of the parent’s
address space when the child
process attempts to write to it.
Investigate using DECthreads
software. (See the Guide to
DECthreads.)
Differences Between DIGITAL UNIX and ULTRIX System Calls C–1