[#BloombergLP-bdlb-Float-signBit-04bb]
= xref:BloombergLP.adoc[BloombergLP]::xref:BloombergLP/bdlb.adoc[bdlb]::xref:BloombergLP/bdlb/Float.adoc[Float]::signBit
:relfileprefix: ../../../
:mrdocs:

Return `true` if the sign bit of `number` is set.

== Synopsis

Declared in `<bdlb_float.h>`

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

== Description

This function is equivalent to the `signbit` macro in C99. Note that this function will return `true` for some NaNs, even though the concepts of negative and positive do not apply to NaNs.

== Return Value

`true` if the sign bit of `number` is set, and `false` otherwise

== Parameters

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


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