Editing NaN (section)

== Display ==
Different operating systems and programming languages may have different string representations of NaN.

 nan (C, C++, Python)
 NaN (ECMAScript, Rust, C#, Julia, Java). <small>Julia may show alternative NaN, depending on precision, NaN32, and NaN16; NaN is for Float64 type.</small>
 NaN% 
 NAN (C, C++, Rust)
 NaNQ (IBM XL and AIX: Fortran, C++ proposal n2290)
 NaNS (ditto)
 qNaN
 sNaN
 1.#SNAN (Excel)
 1.#QNAN (Excel)
 -1.#IND (Excel)
 +nan.0 (Scheme)

Since, in practice, encoded NaNs have a sign, a quiet/signaling bit and optional 'diagnostic information' (sometimes called a ''payload''), these will occasionally be found in string representations of NaNs, too. Some examples are:

* For the C and C++ languages, the sign bit is always shown by the standard-library functions (e.g. {{code|-nan}}) when present. There is no standard display of the payload nor of the signaling status, but a quiet NaN value of a specific payload may either be constructed by providing the string <code>nan(''char-sequence'')</code> to a number-parsing function (e.g. {{code|strtod}}) or by providing the ''char-sequence'' string to {{code|nan()}} (or {{code|nans()}} for sNaN), both interpreted in an implementation-defined manner.
** [[GNU C Compiler|GCC]] and [[LLVM]] provides built-in implementations of {{code|nan()}} and {{code|nans()}}. They parse the ''char-sequence'' as an integer for {{code|strtoull}} (or a differently-sized equivalent) with its detection of integer bases.
** The [[GNU C Library]]'s float-parser uses the ''char-sequence'' string in "some unspecified fashion".<ref>{{cite web |url=https://www.gnu.org/software/libc/manual/html_node/Parsing-of-Floats.html |title=Parsing of Floats (The GNU C Library) |website=www.gnu.org |access-date=9 September 2021 |quote=If ''chars…'' are provided, they are used in some unspecified fashion to select a particular representation of NaN (there can be several).}}</ref> In practice, this parsing has been equivalent to GCC/LLVM's for up to 64 bits of payload.<!-- bug 28322: stable but undocumented behavior -->
** [[Newlib]] does not implement {{code|nan()}} parsing, but {{code|strtod()}} accepts a hexadecimal format without prefix.
** [[musl]] does not implement any payload parsing.

Not all languages admit the existence of multiple NaNs. For example, ECMAScript only uses one NaN value throughout.