A **coroutine** is used to perform multiple tasks at the same time from within
the same script. Such tasks might include producing values from inputs or
performing work on a subroutine when solving a larger problem. A task doesn't
even need to have a defined ending point, but it does need to define
particular times at which it **yields** (pause) to let other things be worked
on.

## Using Coroutines

A new coroutine can be created by providing a function to
`Library.coroutine.create()`. Once created, a coroutine doesn't begin running
until the first call to `Library.coroutine.resume()` which passes the
arguments to the function. This call returns when the function either halts or
calls `Library.coroutine.yield()` and, when this happens,
`Library.coroutine.resume()` returns either the values returned by the
function, the values sent to `Library.coroutine.yield()`, or an error message.
If it does error, the second return value is the thrown error.

```lua
local function task(...)
	-- This function might do some work for a bit then yield some value
	coroutine.yield("first")  -- To be returned by coroutine.resume()
	-- The function continues once it is resumed again
	return "second"
end

local taskCoro = coroutine.create(task)
-- Call resume for the first time, which runs the function from the beginning
local success, result = coroutine.resume(taskCoro, ...)
print(success, result)  --> true, first (task called coroutine.yield())
-- Continue running the function until it yields or halts
success, result = coroutine.resume(taskCoro)
print(success, result)  --> true, second (task halted because it returned "second")
```

During the lifetime of the coroutine, you can call
`Library.coroutine.status()` to inspect its status:

<table>
    <thead>
        <tr>
            <th>Status</th>
            <th>Meaning</th>
        </tr>
    </thead>
    <tbody>
        <tr>
            <td><b>suspended</b></td> <td>The coroutine is waiting to be
            resumed. Coroutines begin in this state and enter it when their
            function calls <code>coroutine.yield()</code>.</td>
        </tr>
        <tr>
            <td><b>running</b></td>
            <td>The coroutine is running right now.</td>
        </tr>
        <tr>
            <td><b>normal</b></td> <td>The coroutine is awaiting the yield of
            another coroutine; in other words, it has resumed another
            coroutine.</td>
        </tr>
        <tr>
            <td><b>dead</b></td> <td>The function has halted (returned or
            thrown an&nbsp;error). The coroutine cannot be used further.</td>
        </tr>
    </tbody>
</table>

### Wrapping Coroutines

When working with coroutines, you can also forgo the use of the coroutine
object and instead use a wrapper function. Such a wrapper function will resume
a particular coroutine when it is called and will return only the yielded
values. You can do this using `Library.coroutine.wrap()`:

```lua
-- Create coroutine and return a wrapper function that resumes it
local f = coroutine.wrap(task)
-- Resume the coroutine as if we called coroutine.resume()
local result = f()
-- If an error occurs it will be raised here!
-- This differs from coroutine.resume() which acts similar to pcall()
```

The first value returned from `Library.coroutine.resume()` describes whether a
coroutine ran without errors. However, functions returned by
`Library.coroutine.wrap()` will not do this: instead they directly return the
values returned or passed to `Library.coroutine.yield()`, if any. Should an
error have occurred while running the coroutine function, the error is raised
on the call of the returned function.

### Producer Pattern Example

Imagine a task that produces repetitions of a word: each time it produces a
repetition, the next one will produce one more. For example, providing `Hello`
will produce `Hello`, `HelloHello`, `HelloHelloHello`, etc. To do this, you
can define `repeatThis()`:

```lua
-- This function repeats a word every time its coroutine is resumed
local function repeatThis(word)
	local repetition = ""
	while true do
		-- Do one repetition then yield the result
		repetition = repetition .. word
		coroutine.yield(repetition)
	end
end
```

To run this function as a coroutine, you can use `Library.coroutine.create()`
followed by multiple calls to `Library.coroutine.resume()`:

```lua
local repetitionCoro = coroutine.create(repeatThis)
print(coroutine.resume(repetitionCoro, "Hello"))  -- true, Hello
print(coroutine.resume(repetitionCoro))           -- true, HelloHello
print(coroutine.resume(repetitionCoro))           -- true, HelloHelloHello
```

For this producer function, you can also use `Library.coroutine.wrap()` to get
a function that produces values:

```lua
local f = coroutine.wrap(repeatThis)
print(f("Hello"))  -- Hello
print(f())         -- HelloHello
print(f())         -- HelloHelloHello
```


Closes and puts the provided coroutine in a dead state. This function
returns `true` unless the coroutine is in an error state, in which case it
returns `false` and the error message. A coroutine that is currently
running cannot be closed. A coroutine cannot be resumed after it is
closed.


coroutine.close

`true` unless the coroutine being closed is in an error state.


Closes and puts the provided coroutine in a dead state.


Creates a new coroutine, with body f. f must be a Luau function.


coroutine.create

Returns `true` if the coroutine this function is called within can safely
yield. Yielding a coroutine inside metamethods or C functions is
prohibited, with the exception of `pcall` and `xpcall`.


coroutine.isyieldable

Whether or not the coroutine can safely yield at this point.


Returns `true` if the coroutine this function is called within can safely
yield.


Starts or continues the execution of coroutine `co`. The first time you
resume a coroutine, it starts running its body. The values `...` are
passed as the arguments to the body function. If the coroutine has
yielded, resume restarts it; the values `...` are passed as the results
from the yield. If the coroutine runs without any errors, resume returns
true plus any values passed to yield (if the coroutine yields) or any
values returned by the body function (if the coroutine terminates). If
there is any error, resume returns false plus the error message.


coroutine.resume

Starts or continues the execution of coroutine `co`.


coroutine.running

Returns the status of coroutine co, as a string: 'running', if the
coroutine is running (that is, it called status); 'suspended', if the
coroutine is suspended in a call to yield, or if it has not started
running yet; 'normal' if the coroutine is active but not running (that is,
it has resumed another coroutine); and 'dead' if the coroutine has
finished its body function, or if it has stopped with an error.


coroutine.status

Returns the status of coroutine co as a string.


Creates a new coroutine, with body f. f must be a Luau function. Returns a
function that resumes the coroutine each time it is called. Any arguments
passed to the function behave as the extra arguments to resume. Returns
the same values returned by resume, except the first boolean. In case of
error, propagates the error.


coroutine.wrap

Creates a new coroutine and returns a function that, when called, resumes
the coroutine.


Suspends the execution of the calling coroutine. Any arguments to yield
are passed as extra results to resume. Yielding a coroutine inside
metamethods or C functions is prohibited, with the exception of `pcall`
and `xpcall`.


coroutine.yield

coroutine

A function that executes alongside the main thread.


/reference/engine/libraries/coroutine.yaml

An object that runs connected functions upon a specific occurrence.

Data Type

RBXScriptSignal

Luau

Tuple

Variant

Data type having a value of either true or false.

boolean

Functions are blocks of code that can execute multiple times on command.

function

A sequence of characters, such as letters, numbers, and symbols.

string

A function that executes alongside the main thread.

Library

Overview

Experiences

Avatar

Assets

Open Cloud

Create

Discovery

Localization

Analytics

Design

Scale

Affiliates

Monetize

Education

This method is asynchronous and returns an `Operation`, which represents the current state of the operation. It contains an endpoint path that you can poll to obtain the real response and applicable metadata. See the [documentation]({longRunningOperationsLink}) on long-running operations for more information.
            
The following sections describe the response and metadata objects that are provided when an operation completes.

Beta endpoints are ready for public use. Breaking changes are possible but rare.

This field may be set when creating a resource, but may not be modified by subsequent requests.

These fields may be set when creating a resource, but may not be modified by subsequent requests.

This field may be provided in requests, but will never be included in responses.

Per API Key: {maxInPeriod} requests every {periodInSeconds} seconds per IP Address

This field may be set on responses, but will be ignored in requests.

Note: Rate limits can be lower during high-traffic periods. Certain endpoints have additional rate limits. [Learn more about rate limits]({link}).

{limit} requests per day across all API keys for a user or group

{limit} requests per hour across all API keys for a user or group

{limit} requests per minute across all API keys for a user or group

{limit} requests per second across all API keys for a user or group

{limit} requests per minute per API key owner

{limit} request(s) per second per API key owner

The following API key permissions are required to call this endpoint. For more
information on generating proper keys, see [Manage API keys]({apiKeyReferenceDocLink}).

The following endpoints are available at paths relative to the base URL.

This string is formatted as a [FieldMask](/cloud/reference/types#fieldmask).

A JSON value can be `null`, `boolean`, `string`, `number`, `array`, or `object`.

The following scopes are required for your OAuth 2.0 application to use this endpoint. For more information on how to register an OAuth 2.0 application, see [App registration and review]({oauth2ReferenceDocLink}).

The following objects describe payloads that are accepted or returned. See each individual endpoint for more information on when these objects are used.

This string is formatted as a [Timestamp](/cloud/reference/types#timestamp).

The following scopes are required for your OAuth 2.0 application to use this endpoint. For more information on how to register an OAuth 2.0 application, see [App Registration and Review]({oauth2ReferenceDocLink}).

This allows viewing information about your assets.

This allows uploading and updating assets to Roblox.

This allows granting asset permissions to any subjects (including groups and experiences) and assets your account has access to.

Grants the ability to update badges owned by the user.

This allows viewing information about your commerce items.

This allows editing of your commerce merchant connections.

This allows you to view information about your Creator Store products.

This allows you to modify information about your Creator Store products.

This allows viewing information about your communities.

This allows you to manage community join requests and role updates of lower-ranked community members for your account.

This allows viewing information about your inventory.

Grants access to mange your badges and spend robux.

Grants access to manage your developer products.

Grants access to read information about the experiences you follow.

Grants access to follow and unfollow experiences on your behalf.

Grants access to manage your communities.

Grants permission to read community information.

Grants access to read and write your localization tables

Grants access to manage team collaboration for all experiences you own.

Grants access to manage your experiences and certain information associated with your experiences (e.g. localization information).

Grants access to read your experiences' localization information.

Grants access to modify your experiences' localization preferences.

Grants access to manage your user account.

Grants access to modify user localization preferences.

This grants the ability to publish messages on behalf of users.

This allows sending notifications from your experience to users.

This allows listing secrets associated with your experience.

This allows creating and updating secrets associated with your experience.

Grants access to read about your subscription products.

Grants the ability to read place information.

Grants the ability to edit place information.

This operation grants access to publish new versions of experiences to Roblox.

Grants the ability to read experience information.

Grants the ability to edit experience information.

Allows you to view user restrictions in the experience.

Allows you to edit user restrictions in the experience.

Grants the ability to read user's premium and verified status.

This allows you to view a user's social accounts.

This enables Single Sign-On functionality.

This grants access to read your profile information.

Default Value: {defaultValueStart}{defaultValueEnd}

An array is an ordered list of values. Arrays are useful for storing collections of data.

A set of key-value pairs, where the keys can be any number, string, or object.

This function returns immediately if possible, but can yield the thread that called it until it can return a value.

{nameStart}name{nameEnd} is no longer supported or maintained by Roblox.

This math operation is no longer supported or maintained by Roblox.

This member doesn’t appear in the object browser and is not intended for widespread use.

This member is only accessible only through the command bar. Attempting to access this member from scripts causes an error.

This function can’t pause the Lua thread that called it.

Attempting to access this member in scripts causes an error. You might be able to access this member from Roblox Studio's property window.

This member doesn’t appear in Roblox Studio’s Object Browser.

You can’t create an instance of this class with the Instance.new constructor.

Roblox does not replicate this member across its server-client boundary.

Lua code can’t access this member. You might be able to change its value from the property window in Roblox Studio.

This member is accessible from OpenCloud Luau execution tasks.

This object’s replication behavior is dependent on the player who owns it.

This member is accessible through the command bar and plugins. Attempting to access this member from scripts causes an error.

This member is read only. Attempting to write to this member causes an error.

This property is read-only and is safe to read in unsynchronized threads. Attempting to write to it causes an error.

This member is accessible only in CoreScripts.

Only Roblox CoreScripts can access this member, and it isn’t usable by Players.

You can read and write to this property safely from multiple threads.

This class is a top-level singleton. Retrieve an instance of this class with the GetService function.

Multiple threads can potentially write to this property, so it’s unsafe to read from unsynchronized threads.

This function pauses the Lua thread that called it until it returns a result. This doesn’t interrupt other scripts.

Manage and analyze all your experiences in one convenient place.

Learn with documentation and resources for all creators.

Learn how to create Roblox experiences with guides, tutorials, and code samples.

Build your experiences in Studio, our all-in-one IDE, and deploy to a wide variety of devices.

Dependable ways to offer value over time to your audience

Since March, most creators who used the New Ads Manager experienced a 44% drop in cost per play and an 89% increase in quality play-through rates.

Learn how to create successful ads that drive traffic to your creations

Chart your experience's growth and discover opportunities to improve

Learn how to apply movement to your characters and environments

Learn how to upload or use assets from Store in your creations

Create Avatar items and publish it to Marketplace

Sorted by highest revenue over the last 7 days

Learn about what you can make and sell on the marketplace

The avatar represents every Roblox user as a customizable character

See this thread of cool creations being built by the community

Learn basic modeling techniques in blender

Find models, scripts, and plugins made by other creators

Learn how to cage your avatar items from Roblox's own 3D artist

Learn how to configure characters to ensure all avatar features work properly

Learn how to create objects that interact with the world or other users

Make and sell your first basic clothing item on Roblox

Use Studio's collaboration tools to work with your team at the same time

Check out what’s trending on the Creator Marketplace

Check out what's trending on the Creator Store

Participate in community events held by other Creators

Find tutorials written by the Creator community

Learn how to implement a Connection invite reward system

Keep players engaged and monetized with content updates

Captivate your audience with an enjoyable gameplay cycle

Drive engagement and progress with fun, repetitive gameplay

Kick off your creator journey by making your very first place.

Learn how to create a sliding door without writing any code

Alex shares first-hand experience behind creating the hit experience, JailBreak

Blake found a passion in making realistic, quirky carnival games

The Clemens are the family-owned studio behind hits like The Survival Game

Jasmine is the artist behind some of the most popular avatar items on Marketplace

Jessica is the designer behind imaginative environments like in Alo Yoga

Jenni is the UGC creator and artist behind many popular collaborations

Morphist’s unique style combines cutesy and emo aesthetics

The Riotfall creators travel to find inspiration for their immersive environments

Stephen shares their love of programming tools

Sam shares how they got started designing fashion items that they wish existed

All objects that make up a 3D world, such as parts and lighting

Use data stores to save player progress and handle player position.

Learn about the range of debugging tools available in Studio

See your progress towards your next cash out!

Use the developer console to debug your experience when testing

Adding subscriptions to your experience helps build long term relationships with your user base. Enable subscriptions before December 15, 2023, and enjoy 3 months of lower rates.

Look at the top Experiences out to get inspiration

Get started with Studio, Roblox’s creation engine

Add a few lines of code to unlock new dashboards to understand your onboarding and other funnels and track your in-game economy.

Minty teaches Enyu about constructive solid geometry.

Build live, cross-server events and cutscenes on a structured sequence

Learn how to create timed events for your experiences

Create time-based events for increased discoverability across Roblox. Announce your latest update, highlight an activity, or celebrate a milestone with your players!

Learn about how to target the age group right for your Creation through Experienced Guidelines

Gain knowledge and expertise directly from Roblox

Learn how to implement a friend invite reward system

Understand the basics of how to create a game

Learn how you can control how your data is used to train AI. {linkStart}Read More{linkEnd}

Easily create custom textures using our AI tools

Use our all-in-one creation engine to build anything you can imagine

PolarCub shares all the tips tricks to make UGC items

Learn best practices for blocking out your environments.

Leverage Guilded to build a community for your Creation

Join our incredible cast of creators for a Halloween game jam

Use the head part to create facial animations or trigger emotes

Using metrics to understand where you can improve your gameplay

Figure out how to keep them coming back to your game

User input allow users to interact with your experience environment

Guide players through their first time playing your experience

Create clothing that stretchs and fit over any avatar body

At Roblox, we believe you learn best by doing. Choose one of our guides to explore more of what the platform offers.

Get help writing code and answers to your creation questions

The Lighting and SoundService let you control environmental effects

Learn how to adapt your content to different languages and cultural norms

Object-oriented programming in Luau. When does it make sense?

This walkthrough covers attachments, beams, and some basic scripting concepts that shows you how to set player health to 0 if they touch something

Cultivating an active player base is an instrumental part of developing a successful and enduring game.

Get started with the performance optimization and troubleshooting tool

Microprofiler provides timing information for the task scheduler

Dive deep into frame colors, flame graphs, and more

Learn how module scripts work and when to use them.

Understand how to use metrics to be more successful

Improve the performance of computationally intensive Luau scripts

View your daily benchmarks, insights, and real-time metrics to take {boldStart}{experienceName}{boldEnd} to the next level.

Learn how to use NPCs (non-player characters) in your experiences

@minty creates an obby live from scratch using suggestions from chat

Our platform provides you with unparalleled opportunities to create. Get started by exploring the Creator Hub, Roblox Studio, and our vibrant Creator community.

Our platform provides you with unparalleled opportunities to create.

Our community of award-winning studios and self-taught creators all started here, just like you. 

A principal environment artist at Roblox covers how and why to use packages

Learn how to deal with the most common performance problems.

Staff stream about gravity, material properties, and constraints

Learn about what happens when a user joins an experience

Plugins add additional features or functionality to your creations

Let's tour PolarCub's UGC Homestore! Also, Temprist shows up.

Learn how to drive traffic and awareness to your creations

Catch up on all the highlights from this year's RDC

Learn how to sell and promote avatar items with insights from the experts.

Learn efficient workflows for making avatar items in Blender.

Madison_Hatter2 shows how to texture and publish a simple avatar item.

Learn about what’s possible with our creation engine

Learn hwo to rig an R15 humanoid character model

Make and sell your first basic rigid accessory on Roblox

Get a preview of some of the new features and capabilities coming soon to Roblox

Studio is the tool that lets you create experiences on Roblox

Learn how to use the script editor in Studio to create custom scripts

Andrew shows you where to place your scripts, so they run properly.

Scripting lets you add immersive interactions for your users

Make and sell your first pair of shoes on Roblox.

Learn Studio shortcuts and key commands that make building quicker

Learn how to integrate features that allow players to play with friends

Learn how to integrate features that allow players to play with Connections

Create a Sponsored Ad to get your Creation in front of more Creators

An in-depth look at how to debug your code in Roblox Studio.

Studio is an all-in-one tool for building on Roblox. Try making something today!

Learn how to offer players recurring benefits for a monthly fee

Grow your experience with the help of other Creators

Use the terrain editor to generate and alter terrain in Studio

Experiences like {boldStart}{experienceName}{boldEnd} saw an average +8.5% lift in qualified play through rate with personalization.

Learn about all the best methods for telling time in Roblox experiences.

Translations can help your Creation reach tons of different audiences

Tour the new UGC Homestore template with Minty and SCHLEEMPH

Use the new Style Manager to create, manage, and apply UI styles.

Learn about how to build for Roblox's unique audience

What are they and how you can use them to build

Watch a quick introduction to creating on Roblox, then jump into Studio

Read the latest announcements from Roblox Staff

Manage and grow your creations all in one convenient place

Workspace holds objects that you want the engine to render in your project

Staff stream covering parts, meshes, terrain, and lighting

Build wild obbies, design epic race tracks and decorate every detail.
Your world is waiting! Let’s create something epic.

Intro to texturing for UGC ft. Madison_Hatter2

coroutine

Summary

Functions

Functions

close

Parameters

Returns

create

Parameters

Returns

isyieldable

Returns

resume

Parameters

Returns

running

Returns

status

Parameters

Returns

wrap

Parameters

Returns

yield

Parameters

Returns