Int 21 Fn 5F3A  U - Named Pipes - Local DOSrawwritenmpipe                  [N]

   AX = 5F3Ah
   BX = handle
   CX = buffer length
   DS:DX -> buffer

Return: CF clear if successful
       CX = bytes written
   CF set if error
       AX = error code

Notes: this function was introduced by LAN Manager but is also supported by
     the Novell DOS Named Pipe Extender, Banyan VINES, OS/2 Virtual DOS
     Machines, and others
   not documented in the LAN Manager Toolkit

See Also: AX=5F39h,AX=5F3Bh,INT 2F/AX=118Fh