Calling a method in the context of a specific thread

Background:

I am writing an FXRuby program. My question should be independent of
FXRuby, though.

FXRuby is a GUI for Ruby.

If I understand some of the comments made here (and I probably don’t)
[see subject: interpreter cannot enter in the context from another
thread] it is a bad thing to attempt to run an FXRuby function in a
non-main thread.

So … I have a non-main thread that wants to display a message box
(i.e. “call” FXMessageBox").

How can I invoke FXMessageBox in the context of the main thread?

I can think of all sorts of ugly solutions.

For instance:

  1. Set some global_variable indicating the task I want to perform in the
    main thread.
  2. Do a thread.stop
  3. have a timer in the main thread and have it dispatch based on
    global_variable
  4. save the return code of FXMessageBox in a thread local variable the
    not-main-thread
  5. Do a thread.run to wake up the stopped not-main-thread.

Ugly!

On 09/29/2010 03:22 AM, Ralph S. wrote:

For instance:

  1. Set some global_variable indicating the task I want to perform in the main thread.
  2. Do a thread.stop
  3. have a timer in the main thread and have it dispatch based on global_variable
  4. save the return code of FXMessageBox in a thread local variable the not-main-thread
  5. Do a thread.run to wake up the stopped not-main-thread.
  1. Have a task queue which is read in the main thread. You can even
    store lambdas in there.

Cheers

robert

Robert,

Thursday, September 30, 2010, 12:10:34 AM, you wrote:

RK> On 09/29/2010 03:22 AM, Ralph S. wrote:

[Note: parts of this message were removed to make it a legal post.]

Background:

I am writing an FXRuby program. My question should be independent of FXRuby, though.

FXRuby is a GUI for Ruby.

If I understand some of the comments made here (and I probably don’t) [see subject: interpreter cannot enter in the context from another thread] it is a bad thing to attempt to run an FXRuby function in a non-main thread.

So … I have a non-main thread that wants to display a message box (i.e. “call” FXMessageBox").

How can I invoke FXMessageBox in the context of the main thread?

I can think of all sorts of ugly solutions.

For instance:

  1. Set some global_variable indicating the task I want to perform in the main thread.
  2. Do a thread.stop
  3. have a timer in the main thread and have it dispatch based on global_variable
  4. save the return code of FXMessageBox in a thread local variable the not-main-thread
  5. Do a thread.run to wake up the stopped not-main-thread.

RK> 6) Have a task queue which is read in the main thread. You can even
RK> store lambdas in there.

Please explain more; a lot more.

I am particularly confused how a task queue would work given that
nothing in the main thread can block since that would stop FXRuby’s
message pump.

On Thu, Sep 30, 2010 at 2:26 PM, Ralph S. [email protected]
wrote:

  1. Do a thread.run to wake up the stopped not-main-thread.

RK> 6) Have a task queue which is read in the main thread. You can even
RK> store lambdas in there.

Please explain more; a lot more.

I am particularly confused how a task queue would work given that nothing in the main thread can block since that would stop FXRuby’s message pump.

Actually I do not know RXRuby - I just answered based on the
information in your posting. Maybe there is a queue in FXRuby that is
regularly read from the main thread and which you can use. Actually
you need to be able to interfere with FXRuby’s processing otherwise I
don’t understand how you want to make option 1 work.

Btw, a quick Google revealed this at the top of the list:

http://www.fxruby.org/doc/differences.html#d0e5063

Kind regards

robert

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