Int 2Fh / 1000h         Get SHARE.EXE Installed State                DOS 3.0+

    Determines whether the resident portion of the SHARE program has
    been loaded.

        Entry   AX = 1000h

        Return  AL = 0FFh | 00h   SHARE loaded | not loaded


    Note
    Some operating environments, such as Windows, intercepts this
    multiplex interrupt and always return a nonzero value whether the
    Share program is loaded or not. To determine whether file sharing
    is available, a program should check for error values upon
    returning from carrying out a file-sharing function, such as
    Lock/Unlock File (Int 21h function 5ch).