Wifi LoRa 32 (V2) and Bosch BME680 libraries (libm.a complete?)

Want to connect a Bosch BME680 sensor via I2C to the LoRa 32 V2. Does work on hardware side. I can succesfully scan the sensor on 0x77.

But, if I want to use the original Bosch libraries to read out the values for temterature and others, the library uses the common <math.h> functions sqrtf and powf for data type float.

The library libm.a at …/hardware/heltec/esp32/tools/sdk/lib seens not to be complete in respect to float values.

Is there anything I can do to get raw values compensated already on LoRa 32 and not later on a processing computer?


libm.a(lib_a-ef_pow.o):(.literal+0x80): undefined reference to __ieee754_sqrtf' libm.a(lib_a-ef_pow.o): In function__ieee754_powf’

Solution found: On MacOS it’s not obvious, which platform.txt to edit. The search index of Mac does not search everywhere. The relevant platform.txt I did find at ~/Library/Arduino15/packages/Heltec-esp32/hardware/esp32/0.0.2-rc1

It was necessary to add {compiler.libraries.ldflags} to recipe.c.combine.pattern
Also make sure, there is a -lm at the end of that line to ensure that math.h/libm.a is also included.