23 Semaphore files

 FrontDoor can be controlled by using so called semaphore files. Both
 FD and FM periodically scan for certain file names in the SYSTEM
 directory, and if found, performs a task such as rescanning the
 contents of the NetMail folder, exits to DOS, prevents human callers,
 and more.

 The commercial version furthermore allows you to specify a separate
 semaphore directory (see FDSETUP > Global > Filenames) to allow
 several copies of FM and FD to use the same semaphore files.

 FD uses the lower right hand corner of its main screen to indicate
 that one or more semaphore is present.

 Filename        Programs    Description
 --------------------------------------------------------------------
 FDRESCAN.NOW    FD          Forces FD to discard all mail packets
                             (NOT messages) from the packet directory
                             and rescan the contents of the NetMail
                             folder before rebuilding the packets.

 FMRESCAN.NOW    FM          Forces FM to rebuild its internal list of
                             messages in the NetMail folder.

 FDINSESS.nnn    FD, FM      FD creates this file whenever a mail
                             session is initiated, and when it is
                             dialing a system, attempting to establish
                             a mail session. If FM detects this file,
                             it will not let you renumber the NetMail
                             folder. "nnn" is the task number (0-255).
                             This is not available in the
                             noncommercial version.

 FDINEXIT.nnn    FD          FD creates this file whenever a human
                             caller is detected and passed onto a BBS
                             or other on-line service. When FD
                             returns, it compares the timestamp of
                             FDINEXIT.nnn with the timestamp of
                             FDRESCAN.NOW, and if they do not match, a
                             complete rescan (see FDRESCAN.NOW) is
                             performed. "nnn" is the task number (0-
                             255). In the noncommercial version, this
                             file is not task aware, and is always
                             called "FDINEXIT.NOW".

 FDNOUSER.NOW    FD          Forces FD to refuse human callers. This
                             has the same effect as setting the "Human
                             callers" option, under FD's "Your
                             profile" menu, to "NO". The visual
                             indicator for this semaphore file is
                             "NU".

 FDNOSCAN.NOW    FD          Forces FD to ignore FDRESCAN.NOW.

 FDNOEXIT.NOW    FD          Prevents FD from exiting because of
                             received mail. This has the same effect
                             as setting the "Exit on mail" option,
                             under FD's "Your profile" menu, to "NO".
                             The visual indicator for this semaphore
                             file is "NE".

 NODIAL.FD       FD          While this is not a semaphore file per
                             se, it triggers the display of a visual
                             indicator, "UD".

 FDEXIT.nnn      FD          Forces FD to UNconditionally exit with
                             the errorlevel "nnn". Before FD exits, it
                             removes the file.

 FDRENUM.nnn     FD, FM      FM creates this file whenever you press
                             <Alt-B> to renumber the NetMail folder.
                             When FD detects this file, it will not
                             place any outgoing calls until it can no
                             longer be found. This prevents FD from
                             initiating an outbound session while FM
                             is renumbering the contents of the
                             NetMail folder. "nnn" is the task number
                             (0-255). This is not available in the
                             noncommercial version.

 ROUTE.FD        FD          While this is not a semaphore file per
                             se, it is used to determine if the
                             NetMail folder has to be rescanned (see
                             FDRESCAN.NOW). If the timestamp of this
                             file has changed since FD last checked
                             it, a rescan is forced.