Int 21 Fn 4BEE  - F-driver.sys V1.14+ - Grab Int 21                        [v]

   AX = 4BEEh

Return: AX = 1234h if grab successful
      = 2345h if failed (INT 21 grabbed previously)

Notes: F-DRIVER.SYS is part of the F-PROT virus/trojan protection package by
     Fridrik Skulason
   when called the first time, this function moves the INT 21 monitoring
     code from its original location in the INT 21 chain to be the first
     thing called by INT 21.  This is the mechanism used by F-NET.

See Also: INT 2F/AX=4653h