Yield instruction reference
Yield different custom instructions in your coroutine methods to control when they resume.
Read time 3 minutesLast updated 12 days ago
Coroutines suspend their execution at a statement. A suspends execution of the coroutine until the next frame. But the can also return an instruction for the Unity Editor or runtime to, for example, wait for a specified amount of time or until a condition is met before resuming execution of the coroutine.
yield returnyield return nullyield returnRuntime yield instructions
Unity has a set of custom yield instructions derived from that you can use to resume after a specified time, when a specified conditions is met, or at specific points in the Player loop.
UnityEngine.YieldInstructionInstruction | Description |
|---|---|
| Suspends a coroutine and resumes when an asynchronous operation completes, such as loading a scene or asset. |
| Suspends a coroutine and resumes at the end of the frame, after all rendering and GUI events. Note: |
| Suspends a coroutine and resumes at the end of the next physics update, after all physics calculations. |
| Suspends a coroutine and resumes after a specified number of seconds, taking the time scale into account. |
| Suspends a coroutine and resumes after a specified number of seconds, ignoring the time scale. |
| Suspends a coroutine and resumes when a supplied delegate evaluates to |
| Suspends a coroutine and resumes when a supplied delegate evaluates to |
For more information and example usage of these yield instructions, refer to their API reference pages.
For a visual representation of where different coroutines resume in the Player loop, refer to the diagram in Event function execution order.
UnityTest yield instructions
Unity Test Framework tests marked with the attribute run as coroutines. The Test Framework package adds support for additional yield instructions to control the Unity Editor from tests and provides the possibility to define custom yield instructions.
[UnityTest]Instruction | Description |
|---|---|
| Creates a yield instruction for the Unity Editor to enter Play mode. |
| Creates a yield instruction for the Unity Editor to exit Play mode. |
| Triggers a recompilation of scripts in the Unity Editor. |
| Delays the execution of scripts until after an incoming domain reload. |
For more information on the yield instructions provided by Unity Test Framework, refer to Yield instructions for the Editor.
Editor yield instructions
The Editor coroutines package adds support for coroutines that run in the Unity Editor's Edit mode. The package includes additional yield instructions for Edit mode coroutines.
Instruction | Description |
|---|---|
| Resumes an EditorCoroutine after a specified number of seconds, taking the time scale into account. |
For more information, refer to Editor coroutines.
Batch mode support
All runtime coroutine yield instructions run as normal when you run a standalone Player in batch mode.
If you run the Editor in batch mode and your project has scripts marked with or so that they also run in Edit mode, all runtime coroutines in those scripts run in Edit mode except for . This is because not all Unity subsystems update as regularly in Edit mode as they do at runtime. For more information, refer to the API reference.
[ExecuteInEditMode][ExecuteAlways]WaitForEndOfFrame[ExecuteAlways]Additional resources
- Command-line arguments
- API reference
[ExecuteAlways]