[question] How to use thermal API?

[pille5]

I would like to use the thermal API (https://developer.android.com/ndk/reference/group/thermal) in my native application, but there is no such header in my NDK bundle (v21.0.6113669).

To reproduce the issue you can instert the line #include <android/thermal.h> into the main.cpp of this sample: https://github.com/android/ndk-samples/tree/master/native-activity

Compiler error:

fatal error: 'android/thermal.h' file not found
  #include <android/thermal.h>
           ^~~~~~~~~~~~~~~~~~~
  1 error generated.
  ninja: build stopped: subcommand failed.

I did not find the header, when I tried to search for it in the ndk's directory (search command: find ./ndk-bundle -name 'thermal.h'). There is a thermal.h under the linux directory, but it is not what I need for android builds. I also tried with the latest NDK (v21.2.6472646), but the result was the same. What am I doing wrong?

[enh-google]

that stuff is new in API level 30, so you'll need an Android 11 developer preview/beta and NDK r21c.

i'll get the docs improved to at least include the availability. (danalbert: we should get that into the NDK API review process until/unless we get tool support for automating it.)

[ggfan]

v21.0.6113669. not suppose to have it; v21.2.6472646 has it
It may depend on which/how you configure:

• AGP version
• target/minSDK version ( which decides which API level in the header ) ( whether "R" or 30 )

Thermal is Android R feature, so minSdkVersion must be for "Android R":

• either "R" for Android R Preview
• or 30 for future beta/formal release
  and only one of the above work, you have to try it out ( I am still trying now ).

you could try to follow this one for the example

• project's build.gradle
• app/build.gradle
  If you use the sample's configure, it will work for sure: but it is NOT using formal AGP 4.0.0 release.

I am trying with the formal AGP 4.0.0 version, so far, I could not build with this formal version + formal release of NDK (21.2.6472646). if I get something, I will update you.

[ggfan]

Actually both of your NDK versions does not have new things for Android R, so use the available versions of:
21.1.6363665
21.1.6352464

[pille5]

Thank you guys for the quick answers. It is quite unfortunate that it depends on Android 11, because the same feature exist on the JAVA side since Android 10 (https://source.android.com/devices/architecture/hidl/thermal-mitigation#thermal-api). I just hoped I do not have to write my own wrappers for it.

[DanAlbert]

r21d is the first stable release that will include the API, FYI.

[ggfan]

yeah, NDK API sometimes behind Java API by one generation: getThermalHeadroom() is not part of Android R's NDK Thermal API yet, if you need that one, you would need your wrapper.