ILE C/C++ Programmer's Guide
A diskette unit can only be accessed with a program described file.
An ILE C/C++ program can only process a diskette file sequentially.
The concept of clearing a file or opening a file using append mode does not
apply to diskette files.
The diskette file label name is required when the file is opened.
You specify this label name using the Override Diskette File (OVRDKTF)
command.
If the diskette file is opened for input and:
- if the lrecl parameter is not specified or is specified as zero, the
record length in the data file label on the name on the diskette is used to
determine the length of the records to read.
- if the lrecl parameter is greater than the length of the records on the
diskette file, the records that are read are padded with blanks.
- if the lrecl parameter is less than the length of the records on the
diskette file, the records that are read are truncated.
- if the file type in the diskette file is a source file, a date and
sequence number is appended at the beginning of each record. You must
remove these when writing the record and add 12 bytes to the lrecl parameter
on the open statement.
- Note:
- Output may not always result in an I/O operation to a diskette file.
The I/O buffer must contain enough data to fill an entire track on a
diskette.
When opening a diskette file for output, any files existing on the diskette
are deleted if the data file expiration date is less than or equal to the
system date.
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