safe-cray-ptr, Qsafe-cray-ptr

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

IDE Equivalent

Windows: Data > Assume Cray Pointers Do Not Share Memory Locations
Linux: None

Architectures

IA-32, Intel® EM64T, Intel® Itanium® architecture

Syntax

Linux:	-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.

Alternate Options

Linux: -safe_cray_ptr
Windows: /Qsafe_cray_ptr

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 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 -safe-cray-ptr option produces incorrect results. In the following example, -safe-cray-ptr should not be used:

pointer (pb, b)

pb = loc(a(2))

do i=1, n

b(i) = a(i) +1

enddo