The I/O status block
(IOSB) for QIO functions on magnetic tape devices is shown in
IOSB Contents.
I/O Function Codes lists the status returns for these functions.
(The OpenVMS system messages documentation provides explanations
and suggested user actions for these returns.)
Device-Dependent Information for Tape Devices (in
Magnetic Tape Driver Device Information)
lists the device-dependent data returned in the second longword.
The IO$_SENSEMODE function can be used to return that data.
Figure 6 IOSB Contents
The byte count is the actual number of bytes transferred to
or from the process buffer or the number of files or blocks skipped.
(If an IO$_SKIPRECORD function is terminated by the detection of
a tape mark, the count returned in the IOSB is an unsigned number
reflecting the number of blocks skipped, plus 1.
HP OpenVMS I/O User's Reference Manual
Magnetic Tape Drivers
