about log10() return 0

[yoyou]

Hello,

nRF52840-DK,  SDK17.2,

double b=log10(0.00000226497650146484375);
NRF_LOG_INFO("log10=%d",b);

b retuan 0.0;

why?

The calculation result on the computer is -5.64

   

Best regards

[Jørgen Holmefjord]

Hi,

You need to use NRF_LOG_FLOAT_MARKER and NRF_LOG_FLOAT(val) when printing floats using NRF_LOG, see Logging customization in logger documentation.

Have you checked using a debugger if b is calculated/stored correctly in the double before begin passed to NRF_LOG?

Best regards,
Jørgen

[Jørgen Holmefjord]

Yes, but note that NRF_LOG_FLOAT_MARKER may limit the number of decimals in the output, see the %02 in the format:

#define NRF_LOG_FLOAT_MARKER   "%s%d.%02d"