$SynchronousEvaluation
✖
$SynchronousEvaluation
Details

- A synchronous evaluation is generally triggered by controls in the front end. Controls that may generate synchronous evaluations include Button, EventHandler, and any control that takes a Dynamic value.
- Manipulate may trigger synchronous evaluations, depending upon the value of the SynchronousUpdating and SynchronousInitialization options.
- A synchronous evaluation is the same as a preemptive evaluation. Some controls, such as Button and EventHandler, support an option setting of Method->"Preemptive", which causes the control's evaluations to be synchronous.
- Synchronous evaluations halt the system while being evaluated. A typical use of $SynchronousEvaluation is to write code that should behave differently to prevent halting the system excessively.
Examples
open allclose allBasic Examples (2)Summary of the most common use cases
Typical shift-return evaluations are asynchronous:

https://wolfram.com/xid/0cf48ckd3jo9uoi-6xma71

Evaluations within Dynamic are synchronous by default:

https://wolfram.com/xid/0cf48ckd3jo9uoi-hg3okd

Scope (2)Survey of the scope of standard use cases
Evaluations within DynamicModule Initialization are synchronous by default:

https://wolfram.com/xid/0cf48ckd3jo9uoi-dekkfe

Manipulate has a different default for SynchronousUpdating:

https://wolfram.com/xid/0cf48ckd3jo9uoi-izbgn6

Properties & Relations (3)Properties of the function, and connections to other functions
By default, Button and similar constructs do synchronous evaluation:

https://wolfram.com/xid/0cf48ckd3jo9uoi-ppn5

With the option Method->"Queued", the evaluation is done asynchronously:

https://wolfram.com/xid/0cf48ckd3jo9uoi-euyxb0

Synchronous evaluation in Dynamic is controlled by the SynchronousUpdating option:

https://wolfram.com/xid/0cf48ckd3jo9uoi-l2g8qn

The initialization of DynamicModule is controlled by the SynchronousInitialization option:

https://wolfram.com/xid/0cf48ckd3jo9uoi-g8zisr

Wolfram Research (2015), $SynchronousEvaluation, Wolfram Language function, https://reference.wolfram.com/language/ref/$SynchronousEvaluation.html.
Text
Wolfram Research (2015), $SynchronousEvaluation, Wolfram Language function, https://reference.wolfram.com/language/ref/$SynchronousEvaluation.html.
Wolfram Research (2015), $SynchronousEvaluation, Wolfram Language function, https://reference.wolfram.com/language/ref/$SynchronousEvaluation.html.
CMS
Wolfram Language. 2015. "$SynchronousEvaluation." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/$SynchronousEvaluation.html.
Wolfram Language. 2015. "$SynchronousEvaluation." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/$SynchronousEvaluation.html.
APA
Wolfram Language. (2015). $SynchronousEvaluation. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/$SynchronousEvaluation.html
Wolfram Language. (2015). $SynchronousEvaluation. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/$SynchronousEvaluation.html
BibTeX
@misc{reference.wolfram_2025_$synchronousevaluation, author="Wolfram Research", title="{$SynchronousEvaluation}", year="2015", howpublished="\url{https://reference.wolfram.com/language/ref/$SynchronousEvaluation.html}", note=[Accessed: 17-May-2025
]}
BibLaTeX
@online{reference.wolfram_2025_$synchronousevaluation, organization={Wolfram Research}, title={$SynchronousEvaluation}, year={2015}, url={https://reference.wolfram.com/language/ref/$SynchronousEvaluation.html}, note=[Accessed: 17-May-2025
]}