Below is a utility method that can check if a 4D Server Database is being ran as a service.

The method is based on the command line service controller "sc" commands.

// Method: currentServerServiceStatus // Description // Get the current server service status // // Return // $0 - 1 (Running), 0 (Not running), -1 (Not registered) // ---------------------------------------------------- C_LONGINT($0;$i) C_TEXT($name_t;$cmmd_t;$in_t;$out_t;$err_t) If (Application type=4D Server) & (Folder separator="\\")    $name_t:=Structure file    $i:=Length($name_t)    Repeat       Case of          : ($name_t[[$i]]=".")             $name_t:=Substring($name_t;1;$i-1)          : ($name_t[[$i]]=Folder separator)             $name_t:=Delete string($name_t;1;$i)             $i:=1       End case       $i:=$i-1    Until ($i=0)        $cmmd_t:="sc query \"4DS "+Lowercase($name_t)+"\""    SET ENVIRONMENT VARIABLE("_4D_OPTION_HIDE_CONSOLE";"true")    LAUNCH EXTERNAL PROCESS($cmmd_t;$in_t;$out_t;$err_t)        Case of       : (Position("RUNNING";$out_t)>0)          $0:=1 // current server service is running       : (Position("STOPPED";$out_t)>0)          $0:=0 // current server service is not running    Else       $0:=-1 // current server application is not registered as a service    End case Else    $0:=-2 // This is not 4D Server End if

The method is valid as long as only one instance of the database is being ran. If the database is ran as a service and a second instance is ran as an application, the code will still result in the database being ran as a service as the first instance still appears in the command line's 'sc query' results.

Microsoft Documentation:
More on the Service Controller