#Build2016

Asynchronous programming with C++ UWPEric Mittelette, Program Manager (Visual C++)Gor Nishanov, Software Engineer (Visual C++)Peter Torr, Program Manager (Windows)

General Visual C++ ImprovementsMulti-device developmentCross-platform support for iOS and Android

Standard conformanceC++17 feature-complete for librariesFixed C++11 and C++14 conformance issuesClang/C2 front-end support

Performance

Code generationCompiler throughput

Better IDE supportRefactor -> Rename functionRefactor -> Extract functionImproved Intellisense for templates

Debugger improvementsVisualizationsMemory diagnosticsGraphics diagnostics

Async with WinRT

AcquireConnectionAsyncAddAndShowDeviceAccountsAsyncAddAsyncAddAudioEffectAsyncAddDatagramSocketAsyncAddDeviceAsyncAddEffectAsyncAddLicenseAsyncAddPackageAsyncAddPackageVolumeAsyncAddProfileFromObjectAsyncAddProfileFromXmlAsyncAddStreamSocketListenerAsyncAddVideoEffectAsyncAddWebAccountAsyncAppendLinesAsyncAppendTextAsyncApplyAsyncApproveSessionAsyncAttachAsyncAuthenticateAsyncAuthenticateDeviceAsyncAuthenticateSilentlyAsyncAuthenticateUserAsyncBeginServiceRequestBindEndpointAsyncBindServiceNameAsyncBufferAllAsyncBuildChainAsyncCancelAsyncCancelAsyncOperationsCancelIOAsyncCaptureAsyncCaptureFileAsyncCapturePhotoToStorageFileAsyncCapturePhotoToStreamAsyncCapturePreviewToStreamAsyncCaptureSelectedContentToDataPackageAsyncChangeAdministrativeKeyAsyncChangeAsyncChangeMessageFlagStateAsyncCheckAvailabilityAsyncCheckHealthAsyncClaimDrawerAsyncClaimPrinterAsyncClaimReaderAsyncClaimScannerAsyncCleanupPackageForUserAsyncClearAsyncClearEffectsAsyncClearPublisherCacheFolderAsyncClearRegionsAsyncClearStallAsyncClearTemporaryWebDataAsyncClearViewAsyncClearWebAccountPictureAsyncCloseAndSaveToFileAsyncCommitAsyncCompileConstraintsAsyncCompleteUpdatesAsyncConfigureAccessPointAsyncConnectAsyncConnectProfileAsyncConnectProfileWithPasswordCredentialAsyncConvertBackAsyncConvertContactToVCardAsyncConvertVCardToContactAsync

CopyAndCloseAsyncCopyAndReplaceAsyncCopyAsyncCopyFromFileAsyncCopyProtectionAsyncCopyToAsyncCreateAccountAsyncCreateAnnotationListAsyncCreateAppointmentCalendarAsyncCreateAsyncCreateContactListAsyncCreateCopyFromSurfaceAsyncCreateDashboardItemUpdaterAsyncCreateDeviceAccountAsyncCreateDeviceInputNodeAsyncCreateDeviceOutputNodeAsyncCreateDownloadAsyncCreateEndpointPairAsyncCreateEndpointPairForPortsAsyncCreateFileAsyncCreateFileForUserAsyncCreateFileInputNodeAsyncCreateFileOutputNodeAsyncCreateFolderAsyncCreateFolderForUserAsyncCreateForInPlacePropertyEncodingAsyncCreateForTranscodingAsyncCreateFromFileAsyncCreateFromHResultAsyncCreateFromIdAsyncCreateFromImageFileAsyncCreateFromStreamAsyncCreateFromUriAsyncCreateMailboxAsyncCreateMediaResourceAsyncCreateProtectedAndOpenAsyncCreatePushNotificationChannelForApplicationAsyncCreatePushNotificationChannelForSecondaryTileAsyncCreateRequestAsyncCreateResourceAsyncCreateResponseMessageAsyncCreateSocialFeedUpdaterAsyncCreateStreamedFileAsyncCreateStreamedFileFromUriAsyncCreateUploadAsyncCreateUploadFromStreamAsyncCreateWebAccountWatcherAsyncDeAuthenticateDeviceAsyncDecryptAsyncDecryptTpmAttestationCredentialAsyncDeleteAllAsyncDeleteAnnotationAsyncDeleteAppointmentAsyncDeleteAppointmentInstanceAsyncDeleteAsyncDeleteContactAsyncDeleteContainerAsyncDeleteDeviceAccountAsyncDeleteEntriesAsyncDeleteEntryAsyncDeleteImportedItemsFromSourceAsyncDeleteLicenses

DeleteMessageAsyncDeleteMessagesAsyncDeleteMultipleAsyncDeleteProfileAsyncDeleteResourceAsyncDeleteResourceItemAsyncDeleteWebAccountAsyncDenySessionAsyncDeprovisionAsyncDetectFacesAsyncDeviceInfoSupportsCastingAsyncDeviceInfoSupportsDialAsyncDisableAnnotationAsyncDisableAsyncDisconnectAsyncDisconnectProfileAsyncDownloadAttachmentAsyncDownloadMessageAsyncDropAsyncEnableAsyncEnterAsyncExecuteAsyncFilterUnsupportedSystemFeaturesAsyncFinalizeAsyncFindAccountAsyncFindAccountProviderAsyncFindAccountsAsyncFindAllAdaptersAsyncFindAllAsyncFindAllCardsAsyncFindAllForPackageAsyncFindAllInstancesAsyncFindAllPeersAsyncFindAllProviderWebAccountsAsyncFindAllSourcesAsyncFindAnnotationListsAsyncFindAnnotationsAsyncFindAnnotationsByRemoteIdAsyncFindAnnotationsForContactAsyncFindAppointmentCalendarsAsyncFindAppointmentsAsyncFindAppServiceProvidersAsyncFindChildFoldersAsyncFindConflictAsyncFindConnectionProfilesAsyncFindContactAnnotationListsAsyncFindContactIdsByEmailAsyncFindContactIdsByPhoneNumberAsyncFindContactListsAsyncFindContactsAsyncFindEmailMailboxesAsyncFindExceptionsFromMasterAsyncFindFileHandlersAsyncFindItemsAsyncFindLocalIdsFromRoamingIdAsyncFindLocalLocationsAsyncFindLocationsAsyncFindLocationsAtAsyncFindMailboxesAsyncFindMessagesAsyncFindNearbyAsyncFindRawContactsAsyncFindStartIndexAsyncFindUnexpandedAppointmentsAsyncFindUriSchemeHandlersAsyncFinishAsyncFlushAsyncFocusAsyncForwardMessageAsync

FromBluetoothAddressAsyncFromFolderAsyncFromHostNameAsyncFromIdAsyncFromNetworkAccountIdAsyncFromSmartCardAsyncGenerateSignatureAsyncGetAccountAsyncGetAnnotationAsyncGetAnnotationListAsyncGetAnswerToResetAsyncGetAppAndSupplementalPackageUpdatesAsyncGetAppAndSupplementalPackageUpdatesForUserAsyncGetApplicationLinkAsyncGetApplicationTokenBindingKeyAsyncGetApplicationTokenBindingKeyIdAsyncGetAppListEntriesAsyncGetAppointmentAsyncGetAppointmentCalendarAsyncGetAppointmentInstanceAsyncGetAppPurchaseCampaignIdAsyncGetAppReceiptAsyncGetAppStateAsyncGetAsyncGetAsyncKeyStateGetAttestationAsyncGetAttributedNetworkUsageAsyncGetAuthorityKeyContainerNameAsyncGetBasicPropertiesAsyncGetBitmapAsyncGetBlobInfoAsyncGetBrowsePolicyAsyncGetBufferAsyncGetCachedCapabilitiesAsyncGetCandidatesAsyncGetCapabilitiesAsyncGetCapabilitiesFromNetworkAsyncGetChallengeContextAsyncGetColorProfileAsyncGetConfigurationAsyncGetConnectedProfileAsyncGetConnectivityIntervalsAsyncGetContactAsyncGetContactFromRemoteIdAsyncGetContactListAsyncGetContainerInfoAsyncGetControllersAsyncGetConversationAsyncGetConversationFromThreadingInfoAsyncGetCountAsyncGetCurrentConfigurationAsyncGetCurrentDownloadsAsyncGetCurrentDownloadsForTransferGroupAsyncGetCurrentReadingAsyncGetCurrentUploadsAsyncGetCurrentUploadsForTransferGroupAsyncGetCustomerCollectionsIdAsyncGetCustomerPurchaseIdAsyncGetDataAsyncGetDataBySessionPortAsyncGetDefaultAsyncGetDefaultPrintTicketAsync

GetDeviceAccountConfigurationAsyncGetDeviceSelectorFromCastingSourceAsyncGetDisplayNameAsyncGetDocumentPropertiesAsyncGetDomainNameAsyncGetDrivingRouteAsyncGetDrivingRouteFromWaypointsAsyncGetEndpointPairsAsyncGetEntryAsyncGetExtensionPropertiesAsyncGetFeatureReportAsyncGetFileAsyncGetFileFromApplicationUriAsyncGetFileFromPathAsyncGetFilesAsyncGetFirstNameAsyncGetFolderAsyncGetFolderForUserAsyncGetFolderFromPathAsyncGetFoldersAsyncGetForUserAsyncGetFrameAsyncGetGeopositionAsyncGetGeopositionHistoryAsyncGetGeotagAsyncGetGlyphThumbnailAsyncGetHtmlFormatAsyncGetIdAsyncGetImageAsyncGetImagePropertiesAsyncGetIndexedStateAsyncGetInputReportAsyncGetInputStreamAsyncGetIsAppAllowedToInstallAsyncGetIsApplicableAsyncGetItemAsyncGetItemCountAsyncGetItemsAsyncGetLastNameAsyncGetLibraryAsyncGetLibraryForUserAsyncGetLinguisticAlternativesAsyncGetMailboxAsyncGetMeContactAsyncGetMessageAsyncGetMessageByGlobalUniqueIdAsyncGetMessageByRemoteIdAsyncGetMessageCountsAsyncGetMessagesAsyncGetMusicPropertiesAsyncGetNameAsyncGetNetworkUsageAsyncGetOneTimePassCodeAsyncGetOutputStreamAsyncGetParentAsyncGetPerUserFromPerAppAccountAsyncGetPictureAsyncGetPixelDataAsyncGetPixelsAsyncGetPreviewAsyncGetPreviewFrameAsyncGetPrimaryManagedIdentityForNetworkEndpointAsyncGetPrincipalNameAsyncGetProductReceiptAsyncGetProfilesAsyncGetPropertiesAsyncGetPropertyAsyncGetProtectionInfoAsyncGetProvisioningInfoAsyncGetProxyConfigurationAsyncGetPublicFolderAsync

GetRadiosAsyncGetRecordDetailsAsyncGetRemainingBytesInQuotaAsyncGetResourceMapAsyncGetRestrictionLevelAsyncGetRfcommServicesAsyncGetRfcommServicesForIdAsyncGetRtfAsyncGetScaledImageAsThumbnailAsyncGetSdpRawAttributesAsyncGetSessionInitiationProtocolUriAsyncGetSessionsAndUnregisteredAccountsAsyncGetSessionsAsyncGetSoftwareBitmapAsyncGetSourcesUnseenCountAsyncGetSpecialFolderAsyncGetStatisticsAsyncGetStatusAsyncGetStorageItemsAsyncGetStreamProtectionInfoAsyncGetStringAsyncGetSupportedCastingPlaybackTypesAsyncGetSupportedSymbologiesAsyncGetSyncManagerAsyncGetSyncOnDemandForUserAsyncGetSystemHistoryAsyncGetTextAsyncGetThumbnailAsyncGetThumbnailsAsyncGetTokenSilentlyAsyncGetTransportAsyncGetTransportsAsyncGetUiccAppsAsyncGetUnfulfilledConsumablesAsyncGetUnseenCountAsyncGetUriAsyncGetValueAsFileAsyncGetValueAsStreamAsyncGetVideoPropertiesAsyncGetViewsAsyncGetVoiceCallSupportAsyncGetVoiceCommandAsyncGetWalkingRouteAsyncGetWalkingRouteFromWaypointsAsyncGetWalletItemAsyncGetWebLinkAsyncGoToNextFrameAsyncImportItemAsyncImportItemsAsyncImportPfxDataAsyncIndexFileContentsAsyncInitializeAsyncInsertSlipAsyncInstallCertificateAsyncInstallCommandDefinitionsFromStorageFileAsyncInvalidateCacheAsyncInvokeScriptAsyncIsContainerAsyncIsStoreBlockedByPolicyAsyncIssueCredentialsAsyncIsSupportedAsyncIsSymbologySupportedAsyncLaunchAppForItemAsyncLaunchAsyncLaunchFileAsyncLaunchFolderAsyncLaunchFullTrustProcessForAppAsyncLaunchFullTrustProcessForCurrentAppAsync

LaunchUriAsyncLaunchUriForResultsAsyncLeaveAsyncLeaveConversationAsyncLicenseFetchAsyncLoadAddOnProductInfosAsyncLoadAsyncLoadCurrentAsyncLoadFileFromContainerAsyncLoadFromFileAsyncLoadFromStreamAsyncLoadFromUriAsyncLoadListingInformationAsyncLoadListingInformationByKeywordsAsyncLoadListingInformationByProductIdsAsyncLoadModelFromPackageAsyncLoadMoreItemsAsyncLockAsyncMakeDefaultAccountAsyncMapAllPixelsToTargetAsyncMapRegionOfPixelsToTargetAsyncMarkAllAsSeenAsyncMarkAsSeenAsyncMarkEntriesAsSeenAsyncMarkEntryAsSeenAsyncMarkFolderAsSeenAsyncMarkFolderSyncEnabledAsyncMarkMessageAsBlockedAsyncMarkMessageAsSeenAsyncMarkMessageReadAsyncMarkMessagesAsReadAsyncMarkSourcesAsSeenAsyncMeasureAsyncMergeAndValidateWithDefaultPrintTicketAsyncMoveAndReplaceAsyncMoveAppointmentAsyncMoveAsyncMovePackageToVolumeAsyncOpenAsyncOpenDrawerAsyncOpenKeyPairFromCertificateAsyncOpenReadAsyncOpenSequentialReadAsyncOpenTransactedWriteAsyncOverAsyncPairAsyncPauseAsyncPauseRecordAsyncPickAsyncPickContactAsyncPickContactsAsyncPickMultipleContactsAsyncPickMultipleFilesAsyncPickSaveFileAsyncPickSingleContactAsyncPickSingleDeviceAsyncPickSingleDialDeviceAsyncPickSingleFileAsyncPickSingleFolderAsyncPingAsyncPostAsyncPrepareAdvancedPhotoCaptureAsyncPrepareFileTranscodeAsyncPrepareForCustomAnimatedSwitchAsyncPrepareLowLagPhotoCaptureAsyncPrepareLowLagPhotoSequenceCaptureAsync

PrepareLowLagRecordToCustomSinkAsyncPrepareLowLagRecordToStorageFileAsyncPrepareLowLagRecordToStreamAsyncPrepareMediaStreamSourceTranscodeAsyncPreparePageAsyncPrepareStreamTranscodeAsyncPrepareVariablePhotoSequenceCaptureAsyncProcessEventAsyncProcessNextFrameAsyncProtectAsyncProtectStreamAsyncProvisionAsyncProvisionFromXmlDocumentAsyncPullCookiesAsyncPushCookiesAsyncPutAsyncQueryFileSupportAsyncQueryUriSupportAsyncReadAsBufferAsyncReadAsInputStreamAsyncReadAsStringAsyncReadAsyncReadBatchAsyncReadBufferAsyncReadClientCharacteristicConfigurationDescriptorAsyncReadLinesAsyncReadRecordAsyncReadTextAsyncReadValueAsyncRecognizeAsyncRecognizeWithUIAsyncRedeemTokenForFileAsyncRegisterDatagramSocketAsyncRegisterPackageAsyncRegisterPackageByFullNameAsyncRegisterStreamSocketListenerAsyncRegisterSyncManagerAsyncRegisterTransportAsyncReloadSimulatorAsyncRemoveDeviceAsyncRemoveEffectAsyncRemovePackageAsyncRemovePackageVolumeAsyncRemoveSlipAsyncRenameAsyncRenderAsyncRenderToFileAsyncRenderToStreamAsyncRenewAttestationAsyncRenewSystemComponentsAsyncRepairAsyncReplaceWithStreamedFileAsyncReplaceWithStreamedFileFromUriAsyncReportCompletedAsyncReportConsumableFulfillmentAsyncReportFailedAsyncReportFailureAsyncReportProgressAsyncReportSuccessAsyncRequestAccessAsyncRequestAccessForAppAsyncRequestAddFolderAsyncRequestAnnotationStoreAsyncRequestAppLaunchAsyncRequestAppPurchaseAsyncRequestAsyncRequestAttestedVirtualSmartCardCreationAsync

RequestConfirmationAsyncRequestContentAccessAsyncRequestCreateAsyncRequestCreateForSelectionAsyncRequestCredentialsAsyncRequestCustomPromptAsyncRequestDeleteAsyncRequestDeleteForSelectionAsyncRequestDisambiguationAsyncRequestDownloadAndInstallPackageUpdatesAsyncRequestDownloadAndInstallPackageUpdatesForUserAsyncRequestDownloadPackageUpdatesAsyncRequestDownloadPackageUpdatesForUserAsyncRequestExtensionAsyncRequestLaunchAsyncRequestPinChangeAsyncRequestPinResetAsyncRequestProductPurchaseAsyncRequestProductPurchaseByProductIdAndSkuIdAsyncRequestRemoveFolderAsyncRequestRemovePackageAsyncRequestSetAsNotificationProviderAsyncRequestSetImageFeedAsyncRequestSignAsyncRequestStartCastingAsyncRequestStartProjectingAsyncRequestStoreAsyncRequestTokenAsyncRequestUnconstrainedDownloadsAsyncRequestUnconstrainedUploadsAsyncRequestVerificationAsyncRequestVirtualSmartCardCreationAsyncRequestVirtualSmartCardDeletionAsyncReRegistrationAsyncReserveCallResourcesAsyncResetAsyncResetStatisticsAsyncResolveRecipientsAsyncResumeAsyncResumePickSingleFileAsyncResumeRecordAsyncRetainDeviceAsyncRetrieveDeviceAuthenticationDataAsyncRetrieveFeedAsyncRetrieveMediaResourceAsyncRetrievePropertiesAsyncRetrieveResourceAsyncRetrieveServiceDocumentAsyncRetrieveStatisticsAsyncRetrySendMessageAsyncRunAsyncRunIdleAsyncRunToCompletionAsyncSaveAppointmentAsyncSaveAsAsyncSaveAsyncSaveContactAsyncSaveDraftAsyncSaveEntryAsyncSaveFileAsContainerAsyncSaveMessageAsyncSaveModelToPackageAsync

SavePropertiesAsyncSaveToFileAsyncScanAsyncScanFilesToFolderAsyncScanPreviewToStreamAsyncScheduleAsyncSearchForAllUpdatesAsyncSearchForUpdatesAsyncSelectNewAsyncSelectSettingAsyncSendControlInTransferAsyncSendControlOutTransferAsyncSendFeatureReportAsyncSendIOControlAsyncSendLicenseFetchRequestAsyncSendMessageAndGetReplyAsyncSendMessageAndGetResultAsyncSendMessageAsyncSendOutputReportAsyncSendProximityDetectionResponseAsyncSendProximityDetectionStartAsyncSendQueryCommandAsyncSendRegistrationRequestAsyncSendRequestAsyncSendResponseAsyncSendResponseWithPinAsyncSendSetCommandAsyncSetAccountPictureAsyncSetAccountPictureFromStreamAsyncSetAccountPicturesAsyncSetAccountPicturesFromStreamsAsyncSetActiveProfileAsyncSetActiveSymbologiesAsyncSetAutoAsyncSetBitmapAsyncSetCategoryAsyncSetConfigurationAsyncSetEncodingPropertiesAsyncSetGeotagAsyncSetGeotagFromGeolocatorAsyncSetImageAsyncSetImageFileAsyncSetImageStreamAsyncSetLevelAsyncSetMediaStreamPropertiesAsyncSetPackageVolumeOfflineAsyncSetPackageVolumeOnlineAsyncSetPerAppToPerUserAccountAsyncSetPhraseListAsyncSetPresetAsyncSetPropertiesAsyncSetRegionsAsyncSetRelativeScrollPositionAsyncSetRemoteIdentificationInformationAsyncSetScopeAsyncSetSourceAsyncSetStateAsyncSetValueAsyncSetVersionAsyncSetViewAsyncSetWebAccountPictureAsyncShowAccountErrorResolverAsyncShowAccountSettingsAsyncShowAddAccountAsync

ShowAddAppointmentAsyncShowAppointmentDetailsAsyncShowAsStandaloneAsyncShowAsyncShowAtAsyncShowComposeNewEmailAsyncShowComposeSmsMessageAsyncShowEditNewAppointmentAsyncShowForSelectionAsyncShowPrintUIAsyncShowRemoveAppointmentAsyncShowReplaceAppointmentAsyncShowTimeFrameAsyncSignAsyncSignHashedDataAsyncSignInAsyncSignOutAsyncSignOutUserAsyncStagePackageAsyncStageUserDataAsyncStartAppInstallAsyncStartAsyncStartDragAsyncStartPreviewAsyncStartPreviewToCustomSinkAsyncStartProjectingAsyncStartRecordToCustomSinkAsyncStartRecordToStorageFileAsyncStartRecordToStreamAsyncStartSoftwareTriggerAsyncStartTetheringAsyncStopAsyncStopPreviewAsyncStopProjectingAsyncStopRecognitionAsyncStopRecordAsyncStopSoftwareTriggerAsyncStopTetheringAsyncStoreAsyncSubmitPropertySetUpdatesAsyncSubmitUpdatesAsyncSwapDisplaysForViewsAsyncSwitchAsyncSyncAsyncSynthesizeSsmlToStreamAsyncSynthesizeTextToStreamAsyncTraceOperationCompletionTranscodeAsyncTransmitAsyncTryCancelDownloadMessageAsyncTryCancelMeetingAsyncTryCancelSendMessageAsyncTryComputeLatestMeshAsyncTryCreateFolderAsyncTryCreateOrUpdateAppointmentAsyncTryDeleteFolderAsyncTryEmptyFolderAsyncTryExportAnchorsAsyncTryForwardMeetingAsyncTryGetAutoReplySettingsAsyncTryGetDepthCorrelatedCameraIntrinsicsAsyncTryGetDepthCorrelatedCoordinateMapperAsyncTryGetItemAsyncTryImportAnchorsAsyncTryLinkContactsAsync

TryMoveAsyncTryMoveFolderAsyncTryMoveMessageAsyncTryPartialRepairAsyncTryProposeNewTimeForMeetingAsyncTryReduceFacesAsyncTryRotateAsyncTryRotateToAsyncTryRunAsyncTryRunIdleAsyncTrySaveAnnotationAsyncTrySaveAsyncTrySendIOControlAsyncTrySetAutoReplySettingsAsyncTrySetLockScreenImageAsyncTrySetPreferredSourceForPictureAsyncTrySetPropertyAsyncTrySetSceneAsyncTrySetVideoProfileAsyncTrySetViewAsyncTrySetViewBoundsAsyncTrySetWallpaperImageAsyncTryShowAsStandaloneAsyncTryTiltAsyncTryTiltToAsyncTryUpdateMeetingResponseAsyncTryZoomInAsyncTryZoomOutAsyncTryZoomToAsyncUnblockAsyncUnlinkRawContactAsyncUnlockAsyncUnpairAsyncUnprojectAllPixelsAtCorrelatedDepthAsyncUnprojectRegionPixelsAtCorrelatedDepthAsyncUnprotectAsyncUnprotectStreamAsyncUpdateAppByPackageFamilyNameAsyncUpdateAsyncUpdateFirmwareAsyncUpdateKeyAsyncUpdateMediaResourceAsyncUpdatePackageAsyncUpdateProfileFromObjectAsyncUpdateProfileFromXmlAsyncUpdateResourceAsyncUpdateResourceItemAsyncUpdateSettingsAsyncUpdateStatisticsAsyncUpdateWebAccountPropertiesAsyncUpdateWnsChannelAsyncUpgradeToSslAsyncUriToStreamAsyncValidateCertificatesAsyncVerifyAsyncVerifyResponseAsyncVerifySignatureAsyncWriteAsyncWriteBufferAsyncWriteBytesAsyncWriteClientCharacteristicConfigurationDescriptorAsyncWriteDataAsyncWriteLinesAsyncWriteTextAsyncWriteToStreamAsyncWriteValueAsync

Async APIsWinRT contains over 1,300 Async APIsAny API that might stall the UI is designed to be asynchronous

Leads to more responsive applicationsApps should never appear “hung” due to disk or network latency

Consuming these APIs from C++ can be cumbersome

Demo: Opening a JPGUsing PPL tasks

Async code to open a JPGusing namespace Windows::Storage::Pickers;using namespace concurrency;

auto picker = ref new FileOpenPicker();picker->FileTypeFilter->Append(L".jpg");picker->SuggestedStartLocation = PickerLocationId::PicturesLibrary;

create_task(picker->PickSingleFileAsync()).then([this](Windows::Storage::StorageFile^ file){create_task(file->OpenReadAsync()).then([this] (Windows::Storage::Streams::IRandomAccessStreamWithContentType^ stream) { auto bitmap = ref new BitmapImage(); bitmap->SetSource(stream); theImage->Source = bitmap; });});

Async code to open a JPGusing namespace Windows::Storage::Pickers;using namespace concurrency;

auto picker = ref new FileOpenPicker();picker->FileTypeFilter->Append(L".jpg");picker->SuggestedStartLocation = PickerLocationId::PicturesLibrary;

create_task(picker->PickSingleFileAsync()).then([this](Windows::Storage::StorageFile^ file){ create_task(file->OpenReadAsync()).then([this] (Windows::Storage::Streams::IRandomAccessStreamWithContentType^ stream) { auto bitmap = ref new BitmapImage(); bitmap->SetSource(stream); theImage->Source = bitmap; });});

Async code to open a JPGusing namespace Windows::Storage::Pickers;using namespace concurrency;

auto picker = ref new FileOpenPicker();picker->FileTypeFilter->Append(L".jpg");picker->SuggestedStartLocation = PickerLocationId::PicturesLibrary;

create_task(picker->PickSingleFileAsync()).then([this](Windows::Storage::StorageFile^ file){ create_task(file->OpenReadAsync()).then([this] (Windows::Storage::Streams::IRandomAccessStreamWithContentType^ stream) { auto bitmap = ref new BitmapImage(); bitmap->SetSource(stream); theImage->Source = bitmap; });});

Async code to open a JPGusing namespace Windows::Storage::Pickers;using namespace concurrency;

auto picker = ref new FileOpenPicker();picker->FileTypeFilter->Append(L".jpg");picker->SuggestedStartLocation = PickerLocationId::PicturesLibrary;

create_task(picker->PickSingleFileAsync()).then([this](Windows::Storage::StorageFile^ file){ create_task(file->OpenReadAsync()).then([this] (Windows::Storage::Streams::IRandomAccessStreamWithContentType^ stream) { auto bitmap = ref new BitmapImage(); bitmap->SetSource(stream); theImage->Source = bitmap; });});

There’s got to be a better way!

Coroutines and co_await

Code is trivial if synchronous (open JPEG)void ShowImage(){ auto picker = ref new FileOpenPicker(); picker->FileTypeFilter->Append(L".jpg"); picker->SuggestedStartLocation = PickerLocationId::PicturesLibrary;

auto file = picker->PickSingleFile(); auto stream = file->OpenRead(); auto bitmap = ref new BitmapImage(); bitmap->SetSource(stream); theImage->Source = bitmap;}

Code is trivial if asynchronous (open JPEG)task<void> ShowImageAsync(){ auto picker = ref new FileOpenPicker(); picker->FileTypeFilter->Append(L".jpg"); picker->SuggestedStartLocation = PickerLocationId::PicturesLibrary;

auto file = co_await picker->PickSingleFileAsync(); auto stream = co_await file->OpenReadAsync(); auto bitmap = ref new BitmapImage(); bitmap->SetSource(stream); theImage->Source = bitmap;}

Demo: Opening a JPG (redux)Using co_await

More complex example: reading a socketfuture<void> do_while(function<future<bool>()> body) {

return body().then([=](future<bool> notDone) { return notDone.get() ? do_while(body) : make_ready_future(); });}

future<int> tcp_reader(int total) { struct State { char buf[4 * 1024]; int total; Tcp::Connection conn; explicit State(int total) : total(total) {} }; auto state = make_shared<State>(total); return Tcp::Connect("127.0.0.1", 1337).then( [state](future<Tcp::Connection> conn) { state->conn = std::move(conn); return do_while([state]()->future<bool> { if (state->total <= 0) return make_ready_future(false); return state->conn.read(state->buf, sizeof(state->buf)).then( [state](future<int> nBytesFut) { auto nBytes = nBytesFut.get() if (nBytes == 0) return make_ready_future(false); state->total -= nBytes; return make_ready_future(true); }); }); });}

auto tcp_reader(int total) -> future<int>{ char buf[4 * 1024]; auto conn = co_await Tcp::Connect("127.0.0.1", 1337); for (;;) { auto bytesRead = co_await conn.Read(buf, sizeof(buf)); total -= bytesRead; if (total <= 0 || bytesRead == 0) return total; }}

C++ Coroutines in depth

DART 1.9

Future<int> getPage(t) async { var c = new http.Client(); try { var r = await c.get('http://url/search?q=$t'); print(r); return r.length(); } finally { await c.close(); }}

C#

async Task<string> WaitAsynchronouslyAsync() { await Task.Delay(10000); return "Finished"; }

HACK (programming language)

async function gen1(): Awaitable<int> {  $x =  await Batcher::fetch(1);  $y =  await Batcher::fetch(2); return $x + $y; }

Python: PEP 0492 async def abinary(n): if n <= 0: return 1 l = await abinary(n - 1) r = await abinary(n - 1) return l + 1 + r

C++1z

future<string> WaitAsynchronouslyAsync() { co_await sleep_for(10ms); co_return "Finished"s; }

Coroutines are popular!

Design PrinciplesScalableto billions of concurrent coroutines

Efficientresume and suspend operations comparable in cost to a function call

Seamlessinteraction with existing facilities with no overhead

Open-endedcoroutine machinery allowing library designers to expose high-level semantics such as generators, goroutines, tasks and more

Usablein environments where exceptions are forbidden or not available

Generalized Function

User

Coroutine designer

AsyncGeneratorco_await + co_yield

Generatorco_yield

Taskco_await

Plain old function

Compiler does not care

3 x 2 x 2Three new keywordsco_await co_returnco_yield [syntactic sugar for: await $p.yield_value(expr)]

Two new conceptsAwaitableCoroutine Promise

Two library typescoroutine_handlecoroutine_traits

C++ Coroutines: Layered complexityEverybodySafe by default, novice friendlyUse coroutines and awaitables defined by standard library, boost and other high quality libraries

Power UsersDefine new awaitables to customize await for their environment using existing coroutine types

ExpertsDefine new coroutine types

Coroutines and the C++ StandardTS for C++17Latest draft: http://open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0057r2.pdf

Supported in Visual Studio 2015, Update 2“Experimental” support with /await flag until standardizedFully supported in Windows Store Apps

Clang implementation in progress

Call to ActionStart using co_await in your Universal Windows AppsRemember the /await command-line flag!

Send us your feedbackWindows: Feedback App, choose “Developer Platform” areaVC++: http://visualstudio.uservoice.com/

See more detailed talks on C++ coroutinesMeeting Cpp: https://www.youtube.com/watch?v=YYtzQ355_Co – introductory levelCppCon: https://www.youtube.com/watch?v=_fu0gx-xseY – deep-dive

See additional developer contentRe-visit //build/ on Channel 9Continue your education at Microsoft Virtual Academy online

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