 Quiet NaNs, or qNaNs, do not raise any additional exceptions as they propagate through most operations.The exceptions are where the NaN cannot simply be passed through unchanged to the output, such as in format conversions or certain comparison operations.Signaling NaNs, or sNaNs, are special forms of a NaN that, when consumed by most operations, should raise the invalid operation exception and then, if appropriate, be "quieted" into a qNaN that may then propagate.