# Interpreter cannot enter in the context from another thread **URL:** \ **Category:** Ruby\ **Created:** [September 27, 2010, 10:30pm UTC](https://www.ruby-forum.com/t/interpreter-cannot-enter-in-the-context-from-another-thread/195668 "2010-09-27T22:30:35Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![ralphshnelvar](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/e19adc/32.png) [@ralphshnelvar](https://www.ruby-forum.com/u/ralphshnelvar)\ **Post date:** [September 27, 2010, 10:30pm UTC](https://www.ruby-forum.com/t/interpreter-cannot-enter-in-the-context-from-another-thread/195668/1 "2010-09-27T22:30:35Z")
This is a continuation of the thread: Re: Segmentation Fault; more info? Luis L. said: “Please note that Ruby 1.8.x is not multithread and that the interpreter cannot enter in the context from another thread.” Could use please explain this further? Unless I am missing something, 1.8.7 implements green threads … at least according to Dave T. (pg. 171 in _Programming Ruby 1.9_) ---
**Author:** ![ralphshnelvar](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/e19adc/32.png) [@ralphshnelvar](https://www.ruby-forum.com/u/ralphshnelvar)\ **Post date:** [September 27, 2010, 10:45pm UTC](https://www.ruby-forum.com/t/interpreter-cannot-enter-in-the-context-from-another-thread/195668/2 "2010-09-27T22:45:48Z")
On Sep 27, 5:30 pm, Ralph S. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Could use please explain this further? > > Unless I am missing something, 1.8.7 implements green threads … at least according to Dave T. (pg. 171 in _Programming Ruby 1.9_) Yes, but you’re using FXRuby which is a C component. Since you haven’t provided a sample code that shows the segmentation fault. I must tackle all the possible issues, including the spawn of threads by FXRuby and using Ruby-based callbacks. So, Ruby green threads are OK, as long you don’t mix them with real threads. In your post you mention “4 different threads” We are just guessing all due your lack of code. ---
**Author:** ![ralphshnelvar](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/e19adc/32.png) [@ralphshnelvar](https://www.ruby-forum.com/u/ralphshnelvar)\ **Post date:** [September 27, 2010, 11:02pm UTC](https://www.ruby-forum.com/t/interpreter-cannot-enter-in-the-context-from-another-thread/195668/3 "2010-09-27T23:02:12Z")
Luis, Monday, September 27, 2010, 2:45:09 PM, you wrote: LL\> On Sep 27, 5:30 pm, Ralph S. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > [Note: parts of this message were removed to make it a legal post.] > > This is a continuation of the thread: > > Re: Segmentation Fault; more info? > > Luis L. said: > > “Please note that Ruby 1.8.x is not multithread and that the > > interpreter cannot enter in the context from another thread.” > > Could use please explain this further? > > Unless I am missing something, 1.8.7 implements green threads … at least according to Dave T. (pg. 171 in _Programming Ruby 1.9_) LL\> Yes, but you’re using FXRuby which is a C component. LL\> Since you haven’t provided a sample code that shows the segmentation LL\> fault. I must tackle all the possible issues, including the spawn of LL\> threads by FXRuby and using Ruby-based callbacks. LL\> So, Ruby green threads are OK, as long you don’t mix them with real LL\> threads. In your post you mention “4 different threads” LL\> We are just guessing all due your lack of code. LL\> – LL\> Luis L. Could you please explain what you mean by “interpreter cannot enter in the context from another thread.” Ralph ---
**Author:** ![ralphshnelvar](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/e19adc/32.png) [@ralphshnelvar](https://www.ruby-forum.com/u/ralphshnelvar)\ **Post date:** [September 28, 2010, 10:58am UTC](https://www.ruby-forum.com/t/interpreter-cannot-enter-in-the-context-from-another-thread/195668/4 "2010-09-28T10:58:03Z")
Chuck, CR\> A native thread (e.g. one created by the FXRuby C extension) cannot call back into the ruby runtime context to execute more ruby code without causing lots of pain. Ok … now I’m _really_ confused. FXRuby has a method called addTimeout (Yes … it is camel cased). addTimeout allows you to call back to a Ruby method; either once or repeatedly … e.g. timeout\_ = @app.addTimeout(1000, method\_, :repeat =\> true) method\_ will be invoked once every second in the same thread as the call to addTimeout. This is well documented and seems to work flawlessly. Is this what you are talking about? Ralph ---
**Author:** ![ralphshnelvar](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/e19adc/32.png) [@ralphshnelvar](https://www.ruby-forum.com/u/ralphshnelvar)\ **Post date:** [September 28, 2010, 2:20pm UTC](https://www.ruby-forum.com/t/interpreter-cannot-enter-in-the-context-from-another-thread/195668/5 "2010-09-28T14:20:38Z")
On Sep 28, 5:57 am, Ralph S. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Ok … now I’m _really_ confused. We are more because you’re not showing us what code is generating the fault. All we are trying to do is help you and we are taking guesses to all the possible issues. > FXRuby has a method called addTimeout (Yes … it is camel cased). > > addTimeout allows you to call back to a Ruby method; either once or repeatedly … e.g. > > timeout\_ = @app.addTimeout(1000, method\_, :repeat =\> true) > > method\_ will be invoked once every second in the same thread as the call to addTimeout. This is well documented and seems to work flawlessly. > > Is this what you are talking about? We don’t know because you haven’t show any single line of code. Perhaps it is, perhaps is not, but until you show some code, we can’t help further. ---
**Author:** ![ralphshnelvar](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/e19adc/32.png) [@ralphshnelvar](https://www.ruby-forum.com/u/ralphshnelvar)\ **Post date:** [September 27, 2010, 11:13pm UTC](https://www.ruby-forum.com/t/interpreter-cannot-enter-in-the-context-from-another-thread/195668/6 "2010-09-27T23:13:55Z")
On Sep 27, 2010, at 3:55 PM, Ralph S. wrote: > > > Re: Segmentation Fault; more info? > > > LL\> Yes, but you’re using FXRuby which is a C component. > > > LL\> – > > > LL\> Luis L. > > Could you please explain what you mean by “interpreter cannot enter in the context from another thread.” A native thread (e.g. one created by the FXRuby C extension) cannot call back into the ruby runtime context to execute more ruby code without causing lots of pain. You should show us some code. cr