# Where did event callback happen？

**URL:** https://qa.fmod.com/t/where-did-event-callback-happen/12274
**Category:** FMOD Studio
**Created:** [January 26, 2016, 3:43am UTC](https://qa.fmod.com/t/where-did-event-callback-happen/12274 "2016-01-26T03:43:36Z")
**Posts on this page:** 5
**Page:** 1

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### Author: ![wubugui](https://avatars.discourse-cdn.com/v4/letter/w/dc4da7/32.png) [@wubugui](https://qa.fmod.com/u/wubugui)
#### Post date: [January 26, 2016, 3:43am UTC](https://qa.fmod.com/t/where-did-event-callback-happen/12274/1 "2016-01-26T03:43:36Z")

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I init fmod studio with `FMOD_STUDIO_INIT_NORMAL`.  
But I found there are two fmodstudio thread here.Now I want to know in which thread the event callback happen,either or both?  
thx!

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### Author: ![brett](https://yyz2.discourse-cdn.com/flex036/user_avatar/qa.fmod.com/brett/32/261_2.png) [@brett](https://qa.fmod.com/u/brett)
#### Post date: [January 26, 2016, 4:16am UTC](https://qa.fmod.com/t/where-did-event-callback-happen/12274/2 "2016-01-26T04:16:07Z")

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Usually it is triggered from the Studio Update thread.

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### Author: ![wubugui](https://avatars.discourse-cdn.com/v4/letter/w/dc4da7/32.png) [@wubugui](https://qa.fmod.com/u/wubugui)
#### Post date: [January 26, 2016, 4:54am UTC](https://qa.fmod.com/t/where-did-event-callback-happen/12274/3 "2016-01-26T04:54:31Z")

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> [@](#):
>
> Usually it is triggered from the Studio Update thread.

but the document said “When Studio has been initialized in asynchronous mode, callbacks will be fired from the Studio asynchronous thread”.i have init it with FMOD\_STUDIO\_INIT\_NORMAL.And i have checked that some callback fired from a studio thread,but there is another studio thread.i have no idea whether the callback could happen form the anther one.

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### Author: ![brett](https://yyz2.discourse-cdn.com/flex036/user_avatar/qa.fmod.com/brett/32/261_2.png) [@brett](https://qa.fmod.com/u/brett)
#### Post date: [January 27, 2016, 2:54am UTC](https://qa.fmod.com/t/where-did-event-callback-happen/12274/4 "2016-01-27T02:54:44Z")

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sorry you’re right its the “Studio update thread”. I’ll update my original answer to reflect that. If there are other threads, they are just things like the mixer, loading thread, stream thread etc.

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### Author: ![wubugui](https://avatars.discourse-cdn.com/v4/letter/w/dc4da7/32.png) [@wubugui](https://qa.fmod.com/u/wubugui)
#### Post date: [January 27, 2016, 7:14am UTC](https://qa.fmod.com/t/where-did-event-callback-happen/12274/5 "2016-01-27T07:14:18Z")

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thanks!