ZiLOG Z80-RIO Operating System User's Manual page 165

6.13
READ CURRENT
READ CURRENT
Request vector:
Logical unit
Request code - IE or IF
Data transfer area - address to which data should
be read
Length - number of bytes to read. If this is zero,
no data will be transferred. Otherwise, one
record of data will be transferred. The
number of bytes actually transferred will be
indicated here on return.
Completion return address
Error return address
Completion code
Supplemental parameter information - if the file is
open for random I/O, this field should contain
the address of a three-byte area where the
address of the current record will be returned.
Otherwise, it is unused.
Action:
Unless the length specification is zero, one
record's worth of data is transferred from the
current record. The pointer is left unmoved.
Possible errors:
All DISK ERRORS except PROTECTION (code C3)
are possible.
POINTER ERROR (code CA) - if the back pointer of
the current record does not indicate the
previous record, a pointer error is reported.
The data is still transferred.
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