Console App - DoEvents

General
1

So, in my ignorance, I have written a console app that reads MySQL, parses the recordset, makes a HTTPSocket Get to get some data, parse that data and stuff back into the MySQL database. Any errors discovered get sent in an email using SMTPSecureSocket. I have a few boolean flags that get set/unset in the Do/Loop of the app, and when the work is all done, it can then quit happily.

Reading the docs I see DoEvents. I haven’t used that yet, missed it completely, but would that help me. I spawn threads to read each HTTPSocket, and then I send emails using SMTPSecureSockets, and would DoEVents allows those to run and do their magic and allow me to cut down on my boolean flags ?

(or am I missing the plot?)

This is a Linux console app that gets called by Cron every 5 mins.

Thanks

2

“DoEvents” is something like “goto” - you shouldn’t use it anymore. Try Threads and Timers instead. You will find some samples in your Xojo Example Lib (New Project/ Examples) and also in documentation eBooks.

3

Not entirely true. For event-driven console applications, i.e. things that stay running, the App’s Run event typically should contain some setup code and when just go into a While loop that calls DoEvents until some condition tells it to quit.

4

DoEvents is quite fine in Console applications. What you write is only true for GUI applications.

5

you’re right on that, missed that we re talking about console apps.

6

Even still, DoEvents and GoTo are not on the same level of “badness.” While GoTo is considered bad-practice but acceptable, DoEvents in a GUI or WE app is always a project breaker.

7

I wouldn’t use it anymore when creating something new but I wouldn’t touch intact projects either.
@Thom McGrath : Any plan or hint when xojo will make threads running on different CPU cores?

8

[quote=123449:@Tomas Jakobs]I wouldn’t use it anymore when creating something new but I wouldn’t touch intact projects either.
@Thom McGrath : Any plan or hint when xojo will make threads running on different CPU cores?[/quote]
I’m not with the company anymore, but I’m not aware of any plans anyway.

9

You need DoEvents in a console app to trigger any timers, since a console app has no main event loop.

10

Until that feature comes, if it does, helper apps can be a solution…

11

Yup, I don’t have timers yet, but I spew out a ton of threads with database connections and I increment a variable when each one gets created then decrement when it completes, when variable back to zero, move on.

I then send emails, and I had to put in flags that prevent the app quitting so will add DoEvents to that area and see if it makes it more robust.

Thanks

12

[quote=123621:@Richard Gorbutt]Yup, I don’t have timers yet, but I spew out a ton of threads with database connections and I increment a variable when each one gets created then decrement when it completes, when variable back to zero, move on.

I then send emails, and I had to put in flags that prevent the app quitting so will add DoEvents to that area and see if it makes it more robust.

Thanks[/quote]
Tons of threads isn’t going to make things run faster
But a simple helper that can run as a separate process can since it is its own process that can run on a different core etc

13

When I say a ton of threads, each one is based on a user from the database & then checks a server exists, I thread them because if a server isn’t responding or isn’t there, I’m waiting for a timeout. Rather be concurrent than consecutive :slight_smile:

14

Helpers can be - in fact - concurrent since they are their own process & the OS can schedule them preemptively, they have their own memory space etc
And if one dies / crashes with an exception it won’t take your entire app down