[Tonton Luc]

Hi,

Using the code from this post : http://discuss.visual-prolog.com/viewto ... ight=mutex, the following message is displaying (when a second instance of my application is started tu run).

Question : is it possible to replace this message with my own "beautiful" vpiCommonDialogs::note() ?

[B.Hooijenga]

Hello Tonton,

I use this code for years without problems.

I do not need a note but leaving out fail should do the job

Code: Select all

constants
    error_already_exists = 183. % From MSDN
 
class facts
    okToRunMutex : mutex := erroneous.
    taskwindow : taskwindow := erroneous.
 
class predicates
    okToRun : () determ.
clauses
    okToRun() :-
        try
            okToRunMutex := mutex::createNamed("Gregorius"),
            not(multiThread_native::wait_timeout = okToRunMutex:wait(1))
        catch TraceId do
              LastError = exception::getLastError(),
              if LastError = error_already_exists
                 then
                         vpiCommonDialogs::note("Gregorius is al gestart"),
                         fail
                        % Description = common_exception::getLastErrorDescription(LastError),
                         % vpiCommonDialogs::note(tostring(LastError),Description)
                 else
                        common_exception::continue_unknown(TraceId, classInfo, predicate_name())
              end if
         end try.
 
clauses
    get_taskwindow() = taskwindow.
 
clauses
    run():-
        if okToRun() then
            TaskWindow = taskWindow::new(),
            taskwindow := Taskwindow,
            TaskWindow:show()
        end if.

Kind regards

Ben

[Tonton Luc]

Hi Ben,

Exactly what I need.
Your code works fine.

Thanks for your help.