--sqrt_must_set_errno
In this section:
Syntax
--sqrt_must_set_errno Description
Use this option to disable replacing calls to the library function sqrtf() with the RXv2/RXv3 core instruction FSQRT. This is needed to make the code comply with Standard C, because the FSQRT instruction does not set the C library symbol errno if the argument is out of range.
Caution
This option is set automatically when you choose an RXv2 or RXv3 core device using Project>Options>General Options>Target>Device and select Project>Options>C/C++ Compiler>Floating-point semantics>Strict conformance.