# using the \[when\] timestamp in Screen(flip)

**URL:** https://psychtoolbox.discourse.group/t/using-the-when-timestamp-in-screen-flip/1601
**Category:** Uncategorized
**Created:** [March 10, 2007, 2:09am UTC](https://psychtoolbox.discourse.group/t/using-the-when-timestamp-in-screen-flip/1601 "2007-03-10T02:09:16Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![shtler](https://avatars.discourse-cdn.com/v4/letter/s/848f3c/32.png) [@shtler](https://psychtoolbox.discourse.group/u/shtler)
#### Post date: [March 10, 2007, 2:09am UTC](https://psychtoolbox.discourse.group/t/using-the-when-timestamp-in-screen-flip/1601/1 "2007-03-10T02:09:16Z")

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I'm using the [when] timestamp to execute a Screen Flip at a time one  
second into the future. But i've noticed that it halts execution of  
anymore matlab code until that point occurs. Is this correct? I've  
tried searching the forum and the wiki to see if this is explicitly  
stated anywhere, but it's not. thanks ahead of time for any  
clarification.