Simple Pointers

In addition to the standard assignment operator (=), Prism supports the new Fortran 90 pointer assignment operator =>. For example:

program pnode
type node
integer x,y
type(node), pointer :: next
end type node
type(node), target :: n1,n2,n3
type(node), pointer :: pn1, pn2
...
pn1 => n1
pn2 => n2
i = 0 
end

The following examples assume that a breakpoint has been set at the last statement, i = 0, and show how Prism supports Fortran 90 pointers:

• print pn1 - Prints the value pointed to by pn1, in this case n1.

• print pn1%x - Prints the value of the member x in the object pointed to by pn1 (in this case n1%x).

• assign pn1%x = 3 - Assigns n1%x = 3.

• assign pn1=n3 - Assigns n3 to the value pointed to by pn1 (this has the same effect as assign n1=n3).

• assign pn1=>n3 - Makes pn1 point to n3.

• assign pn1=>pn2 - Makes pn1 point to the same object as pn2.