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How do you print an allocatable array defined in a Fortran type with gdb?

Suppose I have the following Fortran 90 code:

program test

implicit none

type :: t_buzzer
  real(8), allocatable :: alloc_array(:,:)
end type

integer, parameter :: nx=2, ny=3
integer :: ii, jj
real(8) :: fixed_array(nx,ny)
real(8), allocatable :: alloc_array(:,:)
type(t_buzzer) :: buzz

allocate(alloc_array(nx,ny))
allocate(buzz%alloc_array(nx,ny))

do jj=1,ny
  do ii=1,nx
    fixed_array(ii,jj) = 10.0 * real(ii) + real(jj)
  end do
end do

alloc_array = fixed_array
buzz%alloc_array = alloc_array

write(*,*) fixed_array
write(*,*) alloc_array
write(*,*) buzz%alloc_array

deallocate(alloc_array)
deallocate(buzz%alloc_array)

end program test

Running it with gdb, I can use the print function to view the content of fixed_array, but not alloc_array

(gdb) print fixed_array 
$1 = (( 11, 21) ( 12, 22) ( 13, 23) )
(gdb) print alloc_array
$2 = (( 0) )

To view the content of alloc_array I must use

(gdb) print *((real_8 *)alloc_array )@6
$3 = (11, 21, 12, 22, 13, 23)

Now I want to view the content of buzz%alloc_array. None of the above commands work here:

(gdb) print buzz%alloc_array
$4 = (( 0) )
(gdb) print *((real_8 *)buzz%alloc_array )@6
Attempt to extract a component of a value that is not a structure.

From the gdb documentation, it seems like I should use the explore function. But nothing gets printed when I try it:

(gdb) explore buzz
The value of 'buzz' is a struct/class of type 'Type t_buzzer
real(kind=8) :: alloc_array(*,*)
End Type t_buzzer' with the following fields:

  alloc_array = <Enter 0 to explore this field of type 'real(kind=8) (*,*)'>

Enter the field number of choice: 0
'buzz.alloc_array' is an array of 'real(kind=8) (*)'.
Enter the index of the element you want to explore in 'buzz.alloc_array': 1,1

Returning to parent value...

The value of 'buzz' is a struct/class of type 'Type t_buzzer
real(kind=8) :: alloc_array(*,*)
End Type t_buzzer' with the following fields:

  alloc_array = <Enter 0 to explore this field of type 'real(kind=8) (*,*)'>

Enter the field number of choice: 
(gdb)

What should I do to view the content of buzz%alloc_array ?

Antonius
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1 Answers1

0

Just do the same as with a normal array

(gdb) print alloc_array
$1 = (( 11, 21) ( 12, 22) ( 13, 23) )
(gdb) print buzz%alloc_array
$2 = (( 11, 21) ( 12, 22) ( 13, 23) )

Why do you think you need the explore function?

BTW real(8) is ugly and not portable (it does not always mean 8 bytes).

As a workaround you could try this, but I have no way to test it in your GDB version. Maybe this works only with the Archer patch.

(gdb) set lang c
Warning: the current language does not match this frame.
(gdb) print buzz.alloc_array[1]
$10 = {11, 21}
(gdb) print buzz.alloc_array[2]
$11 = {12, 22}
(gdb) print buzz.alloc_array[3]
$12 = {13, 23}
Vladimir F Героям слава
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