ZiLOG Z80-RIO Operating System User's Manual page 182

6.22
QUERY ATTRIBUTES QUERY ATTRIBUTES
Request vector:
Logical unit
Request code - 30 or 31
Data transfer area - address for return of
attributes of the file.
Length - number of bytes of attribute information
to be returned.
Completion return address
Error return address
Completion code
Supplemental parameter information - none
Action:
This command is used for obtaining attribute
information, such as the record count, while a
file is open. The descriptor record is read,
the current information merged into it, and as
many bytes of attribute information as have
been requested are returned to the user. See
the OPEN request for the format of the
returned bytes.
Possible errors:
All DISK ERRORS except PROTECTION (code C3)
are possible.
POINTER ERROR (code
CAl -
the back pointer of
the descriptor record does not indicate the
directory record. No data is returned.
FILE NOT OPEN (code CB) - the logical unit
being accessed is not active. No action is
taken.
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