Getting analog reference and correct analog read error

[VormsThierry]

Hello,
I saw Espressif build some functions for getting the analog reference voltage and for the transfert curve.
This functions doesnt compile in a up to date Arduino ide environnement.
I have the header files, but the strucure type doesn't compile as excpected.

Can you provide exemple in Arduino environnement ?

Best regards

Thierry Vorms