J3/17-218
To: J3
From: Malcolm Cohen
Subject: INTENT(IN) exposition clarification
Date: 2017 October 11


1. Introduction

It has come to light that some people have misinterpreted the wording of
the INTENT(IN) restrictions for pointers.  This paper proposes some
wording clarifications to make this harder to misunderstand.


2. Edits to 17-007r2 (N2137)

[108:33] 8.5.10 INTENT attribute, p6,
         "If an object" -> "If a nonpointer object".
This makes the whole paragraph read:
  "If a nonpointer object has an INTENT attribute, then all of its
   subobjects have the same INTENT attribute."
{This is not a technical change, since if the statement applied to the
 subobjects of the target of a pointer, a contradiction would immediately
 arise.}

[109:0+5,8] Same subclause, NOTE 8.17,
  1st sentence: After "If a dummy argument is a" insert "nonpointer".
  3rd sentence: After "For example, if X is a" insert "nonpointer".
This makes the first sentence read
  "If a dummy argument is a nonpointer derived-type object with a pointer
   component, then the pointer as a pointer is a subobject of the dummy
   argument, but the target of the pointer is not."
and the start of the 3rd sentence becomes
  "For example, if X is a nonpointer dummy argument of derived type with
   an integer pointer component P, and X is INTENT (IN), then the
   statement"
{This makes it crystal clear that the first part of the NOTE is talking
 only about the nonpointer case.  The pointer case is covered by the 2nd
 paragraph of the NOTE - and although interpreting the first part to cover
 the pointer case leads straightaway to a contradiction with the second
 part, it's easy to stop reading prematurely and come to the wrong
 conclusion.}

===END===