Function avr_libc::signbit

pub unsafe extern "C" fn signbit(__x: f64) -> i16

The signbit() function returns a nonzero value if the value of \a __x has its sign bit set. This is not the same as \a __x < 0.0', because IEEE 754 floating point allows zero to be signed. The comparison -0.0 < 0.0' is false, but `signbit (-0.0)' will return a nonzero value.