# pc, Qpc

Enables control of floating-point significand precision.

## Syntax

Linux: | -pc n

macOS: | -pc n

Windows: | /Qpc n

## Arguments

n | Is the floating-point significand precision. Possible values are:
32 | Rounds the significand to 24 bits (single precision).
64 | Rounds the significand to 53 bits (double precision).
80 | Rounds the significand to 64 bits (extended precision).

## Default

-pc80 or /Qpc64 | On Linux* and macOS systems, the floating-point significand is rounded to 64 bits. On Windows* systems, the floating-point significand is rounded to 53 bits.

## Description

This option enables control of floating-point significand precision.

Some floating-point algorithms are sensitive to the accuracy of the significand, or fractional part of the floating-point value. For example, iterative operations like division and finding the square root can run faster if you lower the precision with this option.

Note that a change of the default precision control or rounding mode, for example, by using the [Q]pc32 option or by user intervention, may affect the results returned by some of the mathematical functions.

## IDE Equivalent

None

## Alternate Options

None

Parent topic: Floating-Point Options