MPE/iX Intrinsics Reference Manual (32650-90905)
Chapter 7 375
Command Definitions (HP32208-HPLOACNMPROC)
HPFOPEN
formats are supported only on disk devices.
(ASC) This
itemnum,item
pair is ignored for files opened on a terminal;
records of files on terminals are of undefined length. If the file is to be
redirected to tape or disk, set the value to 0 (fixed-length).
FIFO file must be created with the byte streams (9) record format.
7/I32 Carriage-control:
Passes a value indicating whether or not a carriage-control directive is
supplied in the calling sequence of each FWRITE call that writes records
onto the file. This option is applicable only at file creation.
The following values are valid:
0 No carriage-control directive expected
1 Carriage-control directive expected
Default: 0
Carriage-control is defined only for ASCII files. This option and
itemnum
=53 are exclusive, and attempts to open new files with both binary
and carriage-control directives result in an access violation.
A carriage-control character passed through the
control
parameter of
FWRITE is recognized for files with carriage-control specified in
HPFOPEN/FOPEN. Embedded control characters are treated as data on files
where no carriage-control is specified, and spacing is not invoked for the
file. Specify spacing action on files where carriage-control has been
specified by either embedding the control in the record, indicated with a
control
parameter in the call to FWRITE, or by sending the control code
directly through the
control
parameter of FWRITE.
If a carriage-control character is sent to a file where the control cannot be
executed directly (for example, line spacing characters sent to a disk or
tape file), the control character is embedded as the first byte of the record.
Therefore, the first byte of each record in a disk file having carriage-control
characters enabled contains control information. If carriage-control
characters are sent to other types of files, the control is transmitted to the
driver.
Control codes %400 through %403 are remapped to %100 through %103,
so that they fit into one byte and can be embedded. Records written to the
line printer with control codes %400 through %403 should contain only
control information.
Records written with control codes %400 through %403 and no data
(count=0, or embedded control and count=1) does not cause physical I/O.
For computing record size, the file system considers carriage-control
information as part of the data record. Therefore, specifying the
carriage-control option adds one byte to the record size when the file is
originally created. For example, a specification of
REC=-132,1,F,ASCII;CCTL results in a
recsize
of 133 bytes.