Unsaves a set of registers from a document file. If there
are multiple lines with the same key unsaves the next such
line relative to current location in the file.
Example.
[Unsave Document - End use of In Core document file]
USAGE
.OPERATION: UD S [k], [val1],[val2],[val3]
.DOCUMENT FILE: DOC001
[Enter the name of the file where the registers are to be
found. The first variable after 'UD' is used as a key
for retrieving the desired register set stored in the
document file. In the above example, let us assume [k]
has the value: 4. The document file is searched
for the next entry under this key
number. If this entry consists of the line:
4 3 -1.5 30.8 0.0
then the values -1.5, 30.8, and 0.0 are put into the
register variables [val1],[val2],[val3], respectively.]
'
If more register variables are specified on the operation
line than exist in the document file line, an error
message is printed out. In the above example,
UD S [k],[val1],[val2],[val3],[val4]
would produce an error statement because the number of
registers exceeds the three registers present for that key.]
NOTES
Sequential search is much faster than non-sequential, and
should be used whenever it is certain that no updates have
occurred.
If the specified key is -999 < key < 0 then the routine
searches the document file for a line preceeded by a
semicolon similar to a comment. This line is treated as
as a regular line containing a special key and list of
registers. This allows the retrieval of a limited set of
values like rotation angles which are somehow associated
with the contents of the file. The normal retrieval
process (positive keys) treats these lines like comments.
The document file is left open until closed with 'UD E' or
until another document file is used with 'UD'. This saves
time when there are multiple accesses.
Sequential search means that the document file is searched
until the first occurance of the current key is found,
starting at the current location in the document file. If
a key is not found between the current location and the
end of the file the file is rewound to the beginning and
a second search for the key commences. At the end of a
successful search the file remains open at the line
following the retrieved key.