# NAG CL InterfaceX02ALC (real_​largest)

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## 1Purpose

X02ALC returns the largest positive floating-point number.

## 2Specification

 #include
 double X02ALC
The function may be called by the names: x02alc, nag_machine_real_largest or nag_real_largest_number.

## 3Description

X02ALC is a constant defined in the C Header file.
X02ALC returns the largest positive number in the model of floating-point arithmetic described in the X02 Chapter Introduction. The returned value is equal to $\left(1-{b}^{-p}\right)×{b}^{{e}_{\mathrm{max}}}$, where $b$ is the arithmetic base (see X02BHC) and ${e}_{\mathrm{max}}$ is the maximum exponent (see X02BLC) in the model.

None.

None.

None.

Not applicable.

## 8Parallelism and Performance

X02ALC is not threaded in any implementation.