[#BloombergLP-bdlb-Float-isSignalingNan-0f]
= xref:BloombergLP.adoc[BloombergLP]::xref:BloombergLP/bdlb.adoc[bdlb]::xref:BloombergLP/bdlb/Float.adoc[Float]::isSignalingNan
:relfileprefix: ../../../
:mrdocs:

Return `true` if `number` is a signaling NaN.

== Synopsis

Declared in `<bdlb_float.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
static
bool
isSignalingNan(float number);
----

== Description

An invalid floating‐point value ("signaling NaN" or "SNaN") is never the result of a valid operation ‐‐ it must be produced deliberately (i.e., by calling `bsl::numeric_limits<float>::signaling_NaN()`). If an SNaN is used in a subsequent operation, the result is undefined and may result in a hardware trap leading to a signal. Some platforms do not support signaling NaNs, especially for single‐precision floats, and will convert an SNaN to a QNaN on assignment or copy‐initialization (including argument passing). `isSignalingNan` will always return `false` on such platforms. Note that, because an SNaN is a NaN, if this method returns `true`, then `isNan(x)` will also return `true`.

== Return Value

`true` if `number` is a signaling NaN, and `false` otherwise

== Parameters

[cols="1,4"]
|===
| Name| Description
| *number*
| floating‐point value to test
|===


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