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## *nan-double*

This constant has the value of IEEE double-float NaN (Not-a-Number). It is a legal floating-point value. In arithmetic operations, it produces itself in all cases. See the linked discussion for more details.

NaNs like this one can result from normal arithmetic operations, such zero divided by zero in a function with types declared and compiled so `comp:trust-declarations-switch` is true, but that same call run interpreted may instead signal an error.

See Floating-point infinities and NaNs, and floating-point underflow and overflow in implementation.htm. Also see `*negative-infinity-single*`, `*infinity-double*`, `*infinity-single*`, `*negative-infinity-double*`, and `*nan-single*`

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This page was not revised from the 8.2 page.
Created 2012.5.30.

|  | ToC | DocOverview | CGDoc | RelNotes | FAQ | Index | PermutedIndex
| Allegro CL version 9.0 Unrevised from 8.2 to 9.0. 8.2 version