kCFNumberFloat64Type

kCFNumberFloat64Type is a constant defined within the Core Foundation framework of Apple's operating systems. It represents a 64-bit floating-point number, commonly known as a double-precision floating-point number. This type is used when creating CFNumber objects that store floating-point values.

CFNumber is a toll-free bridged type, meaning it can be used interchangeably with the Foundation framework's NSNumber class. When you create an NSNumber object with a floating-point value, it may internally use a representation corresponding to kCFNumberFloat64Type. This allows for precise representation of a wide range of fractional numbers.

The kCFNumberFloat64Type is part of a set of constants that define different numeric types that can be stored within a CFNumber object. These include integer types of various sizes as well as other floating-point types like kCFNumberFloat32Type for single-precision floats. Using the appropriate type constant when creating a CFNumber can sometimes offer performance or memory usage benefits, although for most common use cases, the automatic type handling by NSNumber is sufficient. Developers working directly with Core Foundation may explicitly use kCFNumberFloat64Type when creating CFNumber objects to ensure the intended data type is stored.