Class SteamCallbacks

Steam callbacks and call results: subscribe by generated struct type, await call results as tasks, or receive every message in raw form through a single event. Handlers run on the main thread, or inline on the polling thread when there is no main-thread SynchronizationContext (e.g. headless). On a pipe initialized with External, subscribing and awaiting throw.

Inheritance
object
SteamCallbacks
Inherited Members
Namespace: Unity.Steamworks.Interop
Assembly: Unity.Steamworks.Interop.dll
Syntax
public static class SteamCallbacks

Properties

ExceptionHandler

Receives exceptions thrown by handlers, which are caught so one subscriber cannot break the others. Defaults to UnityEngine.Debug.LogException.

Declaration
public static Action<Exception> ExceptionHandler { get; set; }
Property Value
Type Description
Action<Exception>

PollIntervalMilliseconds

Milliseconds between polls on the callback thread (default 32, minimum 1).

Declaration
public static int PollIntervalMilliseconds { get; set; }
Property Value
Type Description
int

Methods

CallResultAsync<T>(Func<SteamAPICall_t>, bool)

Starts an async Steam call and returns a task that completes with its result. steamCall runs under the dispatcher's lock, so the result cannot arrive before the task is registered.

Declaration
public static Task<T> CallResultAsync<T>(Func<SteamAPICall_t> steamCall, bool gameServer = false) where T : struct
Parameters
Type Name Description
Func<SteamAPICall_t> steamCall

Invokes the Steamworks API and returns its SteamAPICall_t.
bool gameServer

The call was made on the game-server pipe; only that pipe's shutdown cancels the task.
Returns
Type Description
Task<T>

The call result payload once Steam reports it.
Type Parameters
Name Description
T

The call-result struct produced by the invoked API.
Exceptions
Type Condition
SteamCallResultException

The call did not start, or completed with an IO failure.

CallResultAsync<T>(SteamAPICall_t, bool)

Awaits an already-started async call. Prefer CallResultAsync<T>(Func<SteamAPICall_t>, bool): a result that arrives before this method registers the handle is dropped, and the task never completes.

Declaration
public static Task<T> CallResultAsync<T>(SteamAPICall_t call, bool gameServer = false) where T : struct
Parameters
Type Name Description
SteamAPICall_t call

The handle returned by the Steamworks call to await.
bool gameServer

The call was made on the game-server pipe.
Returns
Type Description
Task<T>

The call result payload once Steam reports it.
Type Parameters
Name Description
T

The call-result struct the invoked API produces.

DeliverQueuedCallbacks(bool)

Runs this pipe's waiting handlers now, on the calling thread, instead of later on the main thread.

Declaration
public static void DeliverQueuedCallbacks(bool gameServer = false)
Parameters
Type Name Description
bool gameServer

Deliver the game-server pipe's callbacks instead of the client pipe's.
Exceptions
Type Condition
InvalidOperationException

The pipe was not initialized with ExternalPoll.

RunFrameCallbacks(bool)

Reads the callbacks waiting on a ExternalPoll pipe and delivers them. On the main thread the handlers run before this returns; from another thread they run later on the main thread.

Declaration
public static void RunFrameCallbacks(bool gameServer = false)
Parameters
Type Name Description
bool gameServer

Read the game-server pipe instead of the client pipe.
Exceptions
Type Condition
InvalidOperationException

The pipe was not initialized with ExternalPoll.

SubmitCallback(HSteamPipe, in CallbackMsg_t, bool)

Delivers one message the application read from the pipe. SteamAPICallCompleted_t messages must be passed too, or awaited call results never complete. Call it before FreeLastCallback: the payload is copied here.

Declaration
public static void SubmitCallback(HSteamPipe pipe, in CallbackMsg_t msg, bool gameServer = false)
Parameters
Type Name Description
HSteamPipe pipe

The pipe the message came from; call results are fetched from it.
CallbackMsg_t msg

The message, as SteamAPI_ManualDispatch_GetNextCallback filled it in.
bool gameServer

The message came from the game-server pipe.
Exceptions
Type Condition
InvalidOperationException

The pipe was not initialized with ExternalPoll.

Subscribe<T>(Action<T>, bool)

Subscribes a handler to a Steam callback by its generated struct type, e.g. Subscribe<PersonaStateChange_t>(...). The handler remains subscribed until Unsubscribe<T>(Action<T>, bool) is called.

Declaration
public static void Subscribe<T>(Action<T> handler, bool gameServer = false) where T : struct
Parameters
Type Name Description
Action<T> handler

Invoked with the decoded callback struct.
bool gameServer

Subscribe on the game-server pipe instead of the client pipe.
Type Parameters
Name Description
T

The callback struct to receive.

Unsubscribe<T>(Action<T>, bool)

Removes a handler added with Subscribe<T>(Action<T>, bool). Later callbacks never reach it, but a delivery already under way uses a snapshot of the handlers, so it may still invoke the removed handler.

Declaration
public static bool Unsubscribe<T>(Action<T> handler, bool gameServer = false) where T : struct
Parameters
Type Name Description
Action<T> handler

The same delegate instance that was passed to Subscribe.
bool gameServer

Unsubscribe from the game-server pipe instead of the client pipe.
Returns
Type Description
bool

true when a matching subscription was found and removed.
Type Parameters
Name Description
T

The callback struct that was subscribed to.

Events

OnCallback

Receives every client-pipe callback in raw form, after the callback's typed subscribers. The payload is valid only inside the handler; see SteamCallbackMessage.

Declaration
public static event Action<SteamCallbackMessage> OnCallback
Event Type
Type Description
Action<SteamCallbackMessage>

OnGameServerCallback

Receives every game-server-pipe callback in raw form; see OnCallback.

Declaration
public static event Action<SteamCallbackMessage> OnGameServerCallback
Event Type
Type Description
Action<SteamCallbackMessage>