a future that becomes satisfied after `deadline`. The result of the future is the time at which it expired, or an error [Status](xref:classgoogle_1_1cloud_1_1Status) if the timer did not run to expiration (e.g. it was cancelled).
MakeRelativeTimer
Create a timer that fires after theduration.
Parameters
Name
Description
duration
std::chrono::duration< Rep, Period >
when should the timer expire relative to the current time.
typename Rep
a placeholder to match the Rep tparam fordurationtype, the semantics of this template parameter are documented instd::chrono::duration<>(in brief, the underlying arithmetic type used to store the number of ticks), for our purposes it is simply a formal parameter.
typename Period
a placeholder to match the Period tparam fordurationtype, the semantics of this template parameter are documented instd::chrono::duration<>(in brief, the length of the tick in seconds, expressed as astd::ratio<>), for our purposes it is simply a formal parameter.
a future that becomes satisfied after `duration` time has elapsed. The result of the future is the time at which it expired, or an error [Status](xref:classgoogle_1_1cloud_1_1Status) if the timer did not run to expiration (e.g. it was cancelled).
MakeUnaryRpc
Make an asynchronous unary RPC.
Parameters
Name
Description
async_call
AsyncCallType
a callable to start the asynchronous RPC.
request
Request const &
the contents of the request.
context
std::unique_ptr< grpc::ClientContext >
an initialized request context to make the call.
typename AsyncCallType
the type ofasync_call. It must be invocable with(grpc::ClientContext*, RequestType const&, grpc::CompletionQueue*). Furthermore, it should return astd::unique_ptr<grpc::ClientAsyncResponseReaderInterface<Response>>>. These requirements are verified byinternal::CheckAsyncUnaryRpcSignature<>, and this function is excluded from overload resolution if the parameters do not meet these requirements.
a future that becomes satisfied when the operation completes.
MakeStreamingReadRpc
Make an asynchronous streaming read RPC.
Reading from the stream starts automatically, and the handler is notified of all interesting events in the stream. Note that then handler is called by any thread blocked on this object'sRun()member function. However, only one callback in the handler is called at a time.
Parameters
Name
Description
async_call
AsyncCallType &&
a callable to start the asynchronous RPC.
request
Request const &
the contents of the request.
context
std::unique_ptr< grpc::ClientContext >
an initialized request context to make the call.
on_read
OnReadHandler &&
the callback to be invoked on each successful Read().
on_finish
OnFinishHandler &&
the callback to be invoked when the stream is closed.
typename AsyncCallType
the type ofasync_call. It must be invocable with parameters(grpc::ClientContext*, RequestType const&, grpc::CompletionQueue*). Furthermore, it should return a type convertible tostd::unique_ptr<grpc::ClientAsyncReaderInterface<Response>>>. These requirements are verified byinternal::AsyncStreamingReadRpcUnwrap<>, and this function is excluded from overload resolution if the parameters do not meet these requirements.
the functor to call on theCompletionQueuethread. It must satisfy thevoid()signature.
typename std::enable_if<>< functor="">::value, int >::type
Returns
Type
Description
void
AsyncWaitConnectionReady
Asynchronously wait for a connection to become ready.
Parameters
Name
Description
channel
std::shared_ptr< grpc::Channel >
the channel on which to wait for state changes
deadline
std::chrono::system_clock::time_point
give up waiting for the state change if this deadline passes
Returns
Type
Description
future< Status >
`future<>` which will be satisfied when either of these events happen: (a) the connection is ready, (b) the connection permanently failed, (c) deadline passes before (a) or (b) happen; the future will be satisfied with [`StatusCode::kOk`](xref:namespacegoogle_1_1cloud_1a90e17f75452470f0f3ee1a06ffe58847ae69fa9a656f76dd8a4d89f21992b2d3a) for (a), [`StatusCode::kCancelled`](xref:namespacegoogle_1_1cloud_1a90e17f75452470f0f3ee1a06ffe58847a971493a769ad0aed23946733ede4a8f1) for (b) and [`StatusCode::kDeadlineExceeded`](xref:namespacegoogle_1_1cloud_1a90e17f75452470f0f3ee1a06ffe58847a4d40d05ef9a0c7b22fb80d1bbf8a72df) for (c)
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-09-04 UTC."],[[["\u003cp\u003eThis page provides documentation for the \u003ccode\u003eCompletionQueue\u003c/code\u003e class in the Google Cloud C++ client library, which manages asynchronous operations and their completion events.\u003c/p\u003e\n"],["\u003cp\u003eThe latest version of the documentation is for version 2.37.0-rc, with a list of documentation available for other releases ranging from 2.36.0 down to 2.10.1.\u003c/p\u003e\n"],["\u003cp\u003eThe \u003ccode\u003eCompletionQueue\u003c/code\u003e class allows users to run an event loop with \u003ccode\u003eRun()\u003c/code\u003e, terminate it with \u003ccode\u003eShutdown()\u003c/code\u003e, and cancel pending operations with \u003ccode\u003eCancelAll()\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eYou can create timers with \u003ccode\u003eMakeDeadlineTimer\u003c/code\u003e or \u003ccode\u003eMakeRelativeTimer\u003c/code\u003e, and use \u003ccode\u003eMakeUnaryRpc\u003c/code\u003e and \u003ccode\u003eMakeStreamingReadRpc\u003c/code\u003e for asynchronous RPC calls.\u003c/p\u003e\n"],["\u003cp\u003e\u003ccode\u003eCompletionQueue\u003c/code\u003e supports asynchronous execution of custom functors via \u003ccode\u003eRunAsync\u003c/code\u003e and waiting for a connection to be ready via \u003ccode\u003eAsyncWaitConnectionReady\u003c/code\u003e.\u003c/p\u003e\n"]]],[],null,["# Class google::cloud::CompletionQueue (2.10.1)\n\nVersion 2.10.1keyboard_arrow_down\n\n- [2.42.0-rc (latest)](/cpp/docs/reference/common/latest/classgoogle_1_1cloud_1_1CompletionQueue)\n- [2.41.0](/cpp/docs/reference/common/2.41.0/classgoogle_1_1cloud_1_1CompletionQueue)\n- [2.40.0](/cpp/docs/reference/common/2.40.0/classgoogle_1_1cloud_1_1CompletionQueue)\n- [2.39.0](/cpp/docs/reference/common/2.39.0/classgoogle_1_1cloud_1_1CompletionQueue)\n- [2.38.0](/cpp/docs/reference/common/2.38.0/classgoogle_1_1cloud_1_1CompletionQueue)\n- [2.37.0](/cpp/docs/reference/common/2.37.0/classgoogle_1_1cloud_1_1CompletionQueue)\n- [2.36.0](/cpp/docs/reference/common/2.36.0/classgoogle_1_1cloud_1_1CompletionQueue)\n- [2.35.0](/cpp/docs/reference/common/2.35.0/classgoogle_1_1cloud_1_1CompletionQueue)\n- [2.34.0](/cpp/docs/reference/common/2.34.0/classgoogle_1_1cloud_1_1CompletionQueue)\n- [2.33.0](/cpp/docs/reference/common/2.33.0/classgoogle_1_1cloud_1_1CompletionQueue)\n- [2.32.0](/cpp/docs/reference/common/2.32.0/classgoogle_1_1cloud_1_1CompletionQueue)\n- [2.31.0](/cpp/docs/reference/common/2.31.0/classgoogle_1_1cloud_1_1CompletionQueue)\n- [2.30.0](/cpp/docs/reference/common/2.30.0/classgoogle_1_1cloud_1_1CompletionQueue)\n- [2.29.0](/cpp/docs/reference/common/2.29.0/classgoogle_1_1cloud_1_1CompletionQueue)\n- [2.28.0](/cpp/docs/reference/common/2.28.0/classgoogle_1_1cloud_1_1CompletionQueue)\n- [2.27.0](/cpp/docs/reference/common/2.27.0/classgoogle_1_1cloud_1_1CompletionQueue)\n- [2.26.0](/cpp/docs/reference/common/2.26.0/classgoogle_1_1cloud_1_1CompletionQueue)\n- [2.25.1](/cpp/docs/reference/common/2.25.1/classgoogle_1_1cloud_1_1CompletionQueue)\n- [2.24.0](/cpp/docs/reference/common/2.24.0/classgoogle_1_1cloud_1_1CompletionQueue)\n- [2.23.0](/cpp/docs/reference/common/2.23.0/classgoogle_1_1cloud_1_1CompletionQueue)\n- [2.22.1](/cpp/docs/reference/common/2.22.1/classgoogle_1_1cloud_1_1CompletionQueue)\n- [2.21.0](/cpp/docs/reference/common/2.21.0/classgoogle_1_1cloud_1_1CompletionQueue)\n- [2.20.0](/cpp/docs/reference/common/2.20.0/classgoogle_1_1cloud_1_1CompletionQueue)\n- [2.19.0](/cpp/docs/reference/common/2.19.0/classgoogle_1_1cloud_1_1CompletionQueue)\n- [2.18.0](/cpp/docs/reference/common/2.18.0/classgoogle_1_1cloud_1_1CompletionQueue)\n- [2.17.0](/cpp/docs/reference/common/2.17.0/classgoogle_1_1cloud_1_1CompletionQueue)\n- [2.16.0](/cpp/docs/reference/common/2.16.0/classgoogle_1_1cloud_1_1CompletionQueue)\n- [2.15.1](/cpp/docs/reference/common/2.15.1/classgoogle_1_1cloud_1_1CompletionQueue)\n- [2.14.0](/cpp/docs/reference/common/2.14.0/classgoogle_1_1cloud_1_1CompletionQueue)\n- [2.13.0](/cpp/docs/reference/common/2.13.0/classgoogle_1_1cloud_1_1CompletionQueue)\n- [2.12.0](/cpp/docs/reference/common/2.12.0/classgoogle_1_1cloud_1_1CompletionQueue)\n- [2.11.0](/cpp/docs/reference/common/2.11.0/classgoogle_1_1cloud_1_1CompletionQueue)\n- [2.10.1](/cpp/docs/reference/common/2.10.1/classgoogle_1_1cloud_1_1CompletionQueue) \nCall the functor associated with asynchronous operations when they complete.\n\nConstructors\n------------\n\n### CompletionQueue\n\n### CompletionQueue\n\nFunctions\n---------\n\n### Run\n\nRun the completion queue event loop. \nNote that more than one thread can call this member function, to create a pool of threads completing asynchronous operations.\n\n### Shutdown\n\nTerminate the completion queue event loop.\n\n### CancelAll\n\nCancel all pending operations.\n\n### MakeDeadlineTimer\n\nCreate a timer that fires at `deadline`.\n\n### MakeRelativeTimer\n\nCreate a timer that fires after the `duration`.\n\n### MakeUnaryRpc\n\nMake an asynchronous unary RPC.\n\n### MakeStreamingReadRpc\n\nMake an asynchronous streaming read RPC. \nReading from the stream starts automatically, and the handler is notified of all interesting events in the stream. Note that then handler is called by any thread blocked on this object's [Run()](/cpp/docs/reference/common/2.10.1/classgoogle_1_1cloud_1_1CompletionQueue#classgoogle_1_1cloud_1_1CompletionQueue_1a9803235c77d3838d14b81f5200b204c4) member function. However, only one callback in the handler is called at a time.\n\n### RunAsync\n\nAsynchronously run a functor on a thread [`Run()`](/cpp/docs/reference/common/2.10.1/classgoogle_1_1cloud_1_1CompletionQueue#classgoogle_1_1cloud_1_1CompletionQueue_1a9803235c77d3838d14b81f5200b204c4)ning the [`CompletionQueue`](/cpp/docs/reference/common/2.10.1/classgoogle_1_1cloud_1_1CompletionQueue).\n\n### RunAsync\n\nAsynchronously run a functor on a thread [`Run()`](/cpp/docs/reference/common/2.10.1/classgoogle_1_1cloud_1_1CompletionQueue#classgoogle_1_1cloud_1_1CompletionQueue_1a9803235c77d3838d14b81f5200b204c4)ning the [`CompletionQueue`](/cpp/docs/reference/common/2.10.1/classgoogle_1_1cloud_1_1CompletionQueue).\n\n### AsyncWaitConnectionReady\n\nAsynchronously wait for a connection to become ready."]]
