1 Version 4.0 -- 5/1/89 dbclrbuf
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NAME: dbclrbuf
FUNCTION:
Drop rows from the row buffer.
SYNTAX:
void dbclrbuf(dbproc, n)
DBPROCESS *dbproc;
DBINT n;
COMMENTS:
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o DB-Library provides a row-buffering service to application pro-
grams. You can turn row buffering on by calling
dbsetopt(dbproc, DBBUFFER, "n") where n is the number of rows
you would like DB-Library to buffer. If buffering is on, you
can then randomly refer to rows that have been read from
SQL Server, using dbgetrow(). See the dbgetrow() manual page
for a discussion of the benefits and penalties of row buffer-
ing.
o The row buffer can become full for two reasons. Either
SQL Server has returned more than the n rows you said you
wanted buffered, or sufficient space couldn't be allocated to
save the row you wanted. When the row buffer is full, dbnex-
trow() returns BUF_FULL and refuses to read in the next row
from SQL Server. Once the row buffer is full, subsequent calls
to dbnextrow() will continue to return BUF_FULL until at least
one row is freed by calling dbclrbuf(). dbclrbuf() always
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frees the oldest rows in the buffer first.
o Once a result row has been cleared from the buffer, it is no
longer available to the program.
o For an example of row buffering, see Example 4 in the
DB-Library Reference Supplement.
PARAMETERS:
dbproc - A pointer to the DBPROCESS structure that provides the
connection for a particular front end/SQL Server process. It
contains all the information that DB-Library uses to manage
communications and data between the front end and SQL Server.
n - The number of rows you want cleared from the row buffer. If
you make n equal to or greater than the number of rows in the
buffer, all but the newest row will be removed. If n is less
than 1, the function call is ignored.
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RETURNS:
None.
SEE ALSO:
dbgetrow, dbnextrow, dbsetopt, options