I am trying to compile a fairly modern fortran code on a Mac with gfortran. Lines like this one ...
allocate(sce, mold=sct)
get errors like this:
Error: Array specification or array-valued SOURCE= expression required in ALLOCATE statement
It seems, then, that gfortran understands SOURCE but not MOLD. However, my gfortran is recent:
gcc version 8.2.0 (MacPorts gcc8 8.2.0_3)
I have seen web pages claiming that gfortran has been able to support MOLD since version 7.something. So surely it should be able to do it with 8.2.0. Is this not true? Is something funny about the Mac version? Can anyone suggest what some other problem might be?
EDIT: If anyone's still there, this toy code works fine:
program awm
integer, dimension(:), allocatable :: sct,sce
integer :: nspec = 100
allocate(sct(nspec))
allocate(sce, mold=sct)
end program
But when sct and sce are derived types, it falls apart:
program awm
type :: r1d
real, allocatable :: a(:)
end type
type(r1d), dimension(:), allocatable :: sct,sce
integer :: nspec = 100
allocate(sct(nspec))
do i = 1,nspec
allocate(sct(i)%a(10))
enddo
allocate(sce, mold=sct)
end program
This returns the error I was having above. You might think the definition of the derived type is kind of weird, even unnecessary. Well, the original code from which this is taken is not my code and I'm not in a position to change it much, and actually, this structuring does have its uses for reasons I don't have time to go into. Thanks.
I am convinced this is a duplicate of this GCC bug https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80708 or is very closely related. You have to wait for a fix. I will put your code in the comment for this bug and not open a new one.