Asynchronous Serial Communications Programmer's Reference Manual (32022-90052)

Chapter 9 245
Intrinsics Reference (cont)
FOPEN
=10 Semi-exclusive access.
=11 Shared access.
Bit (7:1) —Inhibit buffering
aoption .
Not meaningful for asynchronous devices. Buffering is
inhibited by default. (Inhibited buffering means that
your process is assigned no system buffers.) Terminals
always are treated with buffering inhibited.
Bit (5:2)—Multiaccess mode
aoption .
Not meaningful for asynchronous devices.
Bit (4:1)—NOWAIT I/O
aoption .
Determines whether or not NOWAIT I/O is specified for
the file. NOWAIT I/O allows the accessor to initiate an
I/O request and to have control returned before the
completion of the request. Terminal operation with
NOWAIT I/O has the standard NOWAIT ramifications;
that is, Privileged Mode is required, no buffering is
allowed, and IOWAIT or IODONTWAIT must be called
after each I/O request.
=0 NOWAIT I/O not in effect.
=1 NOWAIT I/O in effect.
Bits (3:1)—File copy access
aoption .
Specifies whether or not a file may be treated as a
standard sequential file rather than as a file of its own
type.
=0 File must be accessed as its own type.
=1 File may be accessed as standard
sequential file.
Bits (0:3)—Reserved for MPE/iX. You should set each of
these bits to 0.
recsize 16-bit signed integer by value (optional)
Specifies the size of the logical records in the file. A
positive number is used to represent halfwords, a
negative number to represent bytes. This value
indicates the maximum logical record length allowed if
the records in the file are of variable length.
For terminal and printer files, no rounding up occurs if
you specify a record size consisting of an odd number of
bytes. The record size may be different from that