{{page>en:templates:dosint}} ====== Int 21H, AH=64H ====== ===== Version ===== 3 and higher ===== Brief ===== SET DEVICE DRIVER LOOKAHEAD FLAG ===== Family API ===== ===== Input ===== AH = 64h AL = flag 00h (default) call device driver function 5 (non-dest read) before INT 21/AH=01h,08h,0Ah nonzero don't call driver function 5 CX = 636Ch - Call OS/2 VDM function ===== Return ===== Nothing (MS-DOS) CF set, AX=error code??? (DR DOS 5.0, which does not support this call) ===== Notes ===== This function is called by the DOS 3.3+ PRINT.COM. Under MS-DOS, this function does not use any of the DOS-internal stacks and may thus be called at any time, even during another DOS call ===== See also ===== AH=[[en:docs:dos:api:int21:01|01h]] - AH=[[en:docs:dos:api:int21:08|08h]] - AH=[[en:docs:dos:api:int21:0a|0Ah]] - AX=[[en:docs:dos:api:int21:5d:06|5D06h]] ===== Note ===== Text based on [[http://www.cs.cmu.edu/~ralf/files.html|Ralf Brown Interrupt List Release 61]] {{page>en:templates:int}} {{page>en:templates:fapi}}