Section 11,35: IBCLR

 IBCLR (integer, position)

 A function that returns the value of the first argument with the
 specified bit set to 0 (bit clear).  The low-order bit is position
 0.

 +------+---------+----------+------------+-------------+        
 | Args | Generic | Specific |  Argument  | Result Type |
 +------+---------+----------+------------+-------------+
 |  2   |  IBCLR  |   --     | INTEGER*1  | INTEGER*1   |
 |      |         | IIBCLR   | INTEGER*2  | INTEGER*4   |
 |      |         | JIBCLR   | INTEGER*4  | INTEGER*4   |
 |      |see note | KIBCLR   | INTEGER*8  | INTEGER*8   |
 +------+---------+----------+------------+-------------+

 NOTE: KIBCLR is only available on AXP systems.