(j3.2006) declaring procedure pointers using interface blocks

[Robert Corbett]

Last week, I was asked if the program

       PROGRAM MAIN
         INTERFACE
           REAL FUNCTION F()
           END FUNCTION
         END INTERFACE
         POINTER F
         F => F
       END

is standard conforming.  Normally, I rely on clause 16.3.1 to answer questions 
like this one, but the current version of that text does not deal with procedure 
pointers.  I told the person who asked the question that I thought the program 
should not be standard conforming, because F is declared to be both a pointer 
and an external procedure in the scope of the program (see 12.4.3.2p5 of 
14-007r1).  The person who asked the question said that  gfortran and ifort 
accept the code.  I checked the book Modern Fortran Explained and found the 
example in Section 13.6.1, which gives a similar example.  I assume that in this 
case, the example in Modern Fortran Explained trumps the standard and that 
12.4.3.2p5 needs revision.

Robert Corbett