Re: Problem with LOC intrinsic for assumed size arrays

[Brooks Moses <bmoses at stanford dot edu>]

Paul Thomas wrote:
> > To you and Brooks, yes, I knew that MOLD determined whether the
> > return value was scalar or a rank 1 array.  With respect to MOLD's
> > other array properties (ie, assumed-size, assume-shape, etc), no
> > other property is important.  Indeed, the allocation status of an
> > allocatable MOLD may be unimportant (I haven't investigated this).

I figured you knew that, but it seemed worth confirming along with what 
you appeared to be questioning.  :)

As to allocation status:
> ifort thinks this one is:
>
> program z
>   integer(2), allocatable :: m(:)
>   integer i, s(10)
>   s = (/ (i, i=1,10) /)
>   print*, transfer(s((/2,8,3,6/)),m,8)  ! Is this legal?
> end program z
>
> [prt@localhost prs]# ./a.out
>       2      0      8      0      3      0      6      0
>
> It's exactly what the standard says, isn't it?  The bit pattern defined 
> by the source, projected onto the sink with the type and kind parameters 
> of mold.

My interpretation is that this is indeed behavior required by the 
standard.   The array m() has a well-defined type and kind parameter 
regardless of whether it is allocated or not, and this is all that is 
referenced in this case.

The transfer(s((/2,8,3,6)),m) case may be a bit more interesting, 
however.  For determining whether the result is a scalar or an array, 
the standard refers not to whether MOLD is declared as a scalar or an 
array, but to whether it is "scalar or array valued".  As unallocated 
arrays are undefined and by 2.5.4 they do not have a valid value, it 
seems to me that they are not, strictly speaking, "array valued".

Thus, I would conclude that in the latter case the behavior of the 
transfer intrinsic is undefined by the standard -- but that the compiler 
is not required to throw an error, and it would be a completely 
acceptable extension for it to give the same answer as if m() were 
allocated.

A similar pedantic uncertainty arises if m() is allocated but not 
defined, or for that matter if it is an undefined scalar, when SIZE is 
not given.

- Brooks