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

Chapter 9 241
Intrinsics Reference (cont)
FOPEN
a slash (/), a colon (:), or a period (.). If the string is the
name of a system defined file it will begin with a dollar
sign ($). If the string is the name of a user predefined
file, it can begin with an asterisk (*). You can specify
the remote location of a device as
filename:envid .
If you use one of the system defined files, the file can be
used for either input, ($STDIN, $STDINX) or output,
($STDLIST), but not for both.
Though not required, the use of a formal file designator
is recommended in programs written for asynchronous
devices because of the flexibility it provides. If no
formaldesignator is specified, a temporary nameless
file is assigned that you can read from or write to, but
not save. Note that all character arrays must start on a
halfword boundary.
foptions 16-bit unsigned integer by value (optional)
You can specify various file characteristics by setting
corresponding bit groupings in
foptions . The
correspondence is from right to left, beginning with
bit 15. These characteristics are as follows, proceeding
from the rightmost bit groups to the leftmost bit groups
in the word. Not all of the characteristics specified in
foptions have meaning for asynchronous devices, as
noted in the descriptions of the individual bit settings.
Specifying foptions as zero is equivalent to not
specifying
foptions .
Bits (14:2)—Domain
foptions .
Used to specify the file domain. If you anticipate
redirection of the file to some other device, you should
select a domain of 11 (Old Permanent or Temporary).
=00 The file is a NEW file.
=01 The file is a PERMANENT file.
=10 The file is a TEMPORARY file.
=11 The file is an OLD file.
Bit (13:1)—ASCII/binary
foptions .
Ignored for asynchronous devices. All files not on disk
are treated as ASCII files. Use FCONTROL(27)to
enable transfer of binary data. Set to 1.
=0 Binary.
=1 ASCII.