INT 2fH 1000H: Is Share.Exe Installed?

                                                         Compatibility: 3.0+ 
 Expects: AX    1000H
 Returns: AL    status: 00H = is not installed
                        ffH = is installed
    Info: Checks to see if the DOS SHARE.EXE program (which provides file-
          locking functions) has been executed and is resident in memory.

   Notes: Windows (and maybe others) intercept this vector and always
          return a non-zero.

          To really check to see if file-sharing support is installed, try
          locking a file via DOS fn 5cH and check the error/return code.

See Also: INT 2fH: Multiplex Interrupt
          DOS Functions