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copied!<p>Fortran 90 uses descriptors to represent the dimensions (the shape) of its arrays and to pass assumed-shape array arguments. Also pointers in Fortran are special - they can only point to qualified targets. This allows much better debugger introspection in Fortran than in C/C++. Just use <code>print arr(index)</code> or one of the <code>info</code> commands - no need for fancy stuff.</p> <p>Sample code:</p> <pre><code>program arr real, dimension(40) :: stack_array real, allocatable, dimension(:), target :: heap_array real, dimension(:), pointer :: ptr_array integer :: i ! Interface required because of the assumed-shape array argument interface subroutine foo(bar, baz, qux, ptr) real, dimension(:) :: bar real, dimension(40) :: baz real, dimension(*) :: qux real, dimension(:), pointer :: ptr end subroutine foo end interface allocate(heap_array(40)) forall(i = 1:40) stack_array(i) = i heap_array = stack_array + 2 ptr_array => heap_array print *, stack_array(1) call foo(stack_array, stack_array, stack_array, ptr_array) deallocate(heap_array) end program arr subroutine foo(bar, baz, qux, ptr) real, dimension(:) :: bar real, dimension(40) :: baz real, dimension(*) :: qux real, dimension(:), pointer :: ptr print *, bar(1), baz(1), qux(1), ptr(1) end subroutine foo </code></pre> <p>Compile with debug information and run with <code>gdb</code>:</p> <pre><code>$ gfortran -g -o arr.x arr.f90 && gdb ./arr.x ... (gdb) info locals heap_array = (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, ... ptr_array = (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, ... stack_array = (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, ... (gdb) print heap_array $1 = (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, ... (gdb) print ptr_array(3:7) $2 = (5, 6, 7, 8, 9) ... (gdb) info args bar = (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, ... baz = (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, ... qux = () ptr = (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, ... </code></pre> <p>It cannot show the content of assumed-size array arguments for obvious reasons but you can print each element individually:</p> <pre><code>(gdb) print qux(1) $5 = 1 (gdb) print qux(2) $6 = 2 (gdb) print qux(15) $7 = 15 </code></pre> <p>Note that printing array sections doesn't work on assumed-size array arguments as they are not passed by descriptor and <code>gdb</code> runs into trouble:</p> <pre><code>(gdb) print qux(1:8) $8 = (0, 0, 0, 0, 0, 0, 2.25609053e-43, 0) (gdb) print qux(2:9) $9 = (0, 0, 0, 0, 0, 0, 2.25609053e-43, 0) </code></pre>

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