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Azure / azure-iot-sdk-c

A C99 SDK for connecting devices to Microsoft Azure IoT services
https://azure.github.io/azure-iot-sdk-c
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IoTHubDeviceTwin_SendReportedStateCar is not defined #225

Closed Sneezry closed 6 years ago

Sneezry commented 7 years ago

https://github.com/Azure/azure-iot-sdk-c/blob/master/serializer/samples/devicetwin_simplesample/devicetwin_simplesample.c#L132

tameraw commented 6 years ago

Can you please provide more details?

Sneezry commented 6 years ago

Hi @tameraw, thank you for reply. Device twin sample sends reported twin to IoT Hub using IoTHubDeviceTwin_SendReportedStateCar method, and we can see the code block here: https://github.com/Azure/azure-iot-sdk-c/blob/master/serializer/samples/devicetwin_simplesample/devicetwin_simplesample.c#L132

However, there is nothing about IoTHubDeviceTwin_SendReportedStateCar. In another word, we still have no idea how to send reported twin to IoT Hub with C SDK.

jspaith commented 6 years ago

Correct, you're not going to find an explicit definition for IoTHubDeviceTwin_SendReportedStateCar. It is defined as a helper by the DECLARE_DEVICETWIN_MODEL() macro.

When debugging through the serializer, a lot of times your best bet is to single-step into unclear functions and soon you should hit "paydirt" of the underlying implementation. In this case it will be IoTHubDeviceTwin_SendReportedState_Impl.

You can look at the SendReportedState documentation to understand more details, though in a nutshell this will just send up the state as filled in by the Car variable.

Or... let me know on this thread if I can help explain anything else.

Sneezry commented 6 years ago

@jspaith thank you for the information! I am writing some azure iot device twin samples for our board, and I didn't find anything to explain how to send reported twin with azure iot c sdk either in docs or github sample code. I guess I didn't find the right place. However, I have tried to call IoTHubClient_LL_SendReportedState, and now it works. While I was searching for the information, I found this issue, and I guess that user has the same confusion as me https://github.com/Azure-Samples/iot-hub-feather-huzzah-client-app/issues/17

jspaith commented 6 years ago

@Sneezry Thanks for the link to the other GitHub issue.

What we have today obviously isn't clear enough, so I'm going to add a bunch of additional comments around the SendReportedStateCar function so it's easier to understand without hitting GitHub. It's in branch serializer-dt-comments, I'll get it reviewed and hopefully through our gates by end of day today.

Thanks again for bringing all this to our attention.

jspaith commented 6 years ago

I've merged the change into mainline. I'm closing the issue but feel free to re-open this (or new one) if anything else is needed.