In the IEEE 754-2008 standard (referred to as IEEE 754 henceforth), a signaling NaN or sNaN is a NaN which is
signaling in the sense of being most commonly returned in conjunction with various
exceptions and handling mechanisms defined therefor. This is in contrast to the quiet NaN (qNaN) which rarely signals a floating-point
exception of any kind (IEEE Computer Society 2008).
Within the framework documentation, it is suggested that sNaNs be implemented in such a way as to afford meaningful representations
for uninitialized variables and arithmetic-like enhancements which may naturally
fall beyond the scope of the standard. In particular, sNaNs are largely reserved
for operands which signal exceptions for nearly every general-computational and signaling-computational
operation though, in rare instances, qNaNs may also result from such contexts.