MPE/iX Intrinsics Reference Manual (32650-90905)

394 Chapter7
Command Definitions (HP32208-HPLOACNMPROC)
HPFOPEN
transfer whole blocks leave the next record pointer set to the first record in
the next block. The EOF marker always points at the last record in the file.
For files you have opened NOBUF, the FREADDIR, FWRITEDIR, and FPOINT
intrinsics treat the
recnum parameter as a block number.
Indicate non-RIO access to an RIO file by specifying the file NOBUF. Use the
physical block size from FFILEINFO to determine the maximum transfer
length.
For message files, the file system normally resets
itemnum =46 to zero.
However, a message file can be opened with NOBUF if
itemnum =17 is set to
1; this determines access to the file record-by-record or by block.
If writing to a message file, open it NOBUF if
itemnum =17 to access the file
block-by-block.
Native byte stream access opens NOBUF (1) regardless of the value specified
for this
itemnum . This itemnum is ignored for directories since a physical
block transfer interface is not provided for directories.
(ASC) Not used for asynchronous devices.
47/I32 Numextents:
Passes a value in the range 1..32 that determines the number of extents
for the file. If a value of 1 is specified, the file is created as one contiguous
extent of disk space. If a value greater than 1 is specified, a variable
number of extents (with varying extent sizes) is allocated on a need basis.
This option is applicable only at file creation.
(ASC) Not used for asynchronous devices.
Default: 1
This
itemnum may not be specified when creating hierarchical directories.
48/I32 Reverse VT:
Passes a value indicating whether or not the given device name is to be
allocated on a remote machine. Specify the remote environment in the
same open request, using either the formal designator option or the remote
environment option. Reverse VT behaves nearly the same as a terminal
opened through remote file access, except that no session is required on
the remote machine.
The following values are valid:
0 No reverse VT
1 Reverse VT
Default: 0
49
Reserved for the operating system
50/I32 Final disposition:
Passes a value indicating the final disposition of the file at close time
(significant only for files on disk and magnetic tape). A corresponding