# safe-cray-ptr, Qsafe-cray-ptr

Tells the compiler that Cray* pointers do not alias other variables.

## Syntax

Linux: | -safe-cray-ptr

macOS: | -safe-cray-ptr

Windows: | /Qsafe-cray-ptr

## Arguments

None

## Default

OFF | The compiler assumes that Cray pointers alias other variables.

## Description

This option tells the compiler that Cray pointers do not alias (that is, do not specify sharing memory with) other variables.

## IDE Equivalent

Visual Studio: Data > Assume CRAY Pointers Do Not Share Memory Locations (/Qsafe-cray-ptr)

## Alternate Options

None

## Example

Consider the following:

    pointer (pb, b)
    pb = getstorage()
    do i = 1, n
    b(i) = a(i) + 1
    enddo

By default, the compiler assumes that b and a are aliased. To prevent such an assumption, specify the -safe-cray-ptr (Linux* and macOS) or /Qsafe-cray-ptr (Windows*) option, and the compiler will treat b(i) and a(i) as independent of each other.

However, if the variables are intended to be aliased with Cray pointers, using the option produces incorrect results. In the following example, you should not use the option:

    pointer (pb, b)
    pb = loc(a(2))
    do i=1, n
    b(i) = a(i) +1
    enddo

Parent topic: Advanced Optimization Options