The unw_is_fpreg() routine checks whether register number reg is a floating-point register.
This routine is normally implemented as a macro and applications should not attempt to take its address.
The unw_is_fpreg() routine returns a non-zero value if reg is a floating-point register. Otherwise, it returns a value of 0.
THREAD AND SIGNAL SAFETY
unw_is_fpreg() is thread-safe as well as safe to use from a signal handler.