How to print array size (bound) with gdb for Fortran program

Question

I am a beginner in gdb under Linux. When I try to debug my program compiled with ifort and -c, -g options, I would like to check bound of several arrays. Unfortunately I cannot find in Google any information how to print array bound with gdb debugger.

[update]

I have a module with allocatable,public array, which is allocated correctly in a subroutine from this module. In main program (after calling the subroutine) I try to use whatis and see (*,*) instead of shapes.

Jonathan Dursi · Accepted Answer · 2014-10-07 12:41:11Z

6

You can use the whatis command to view array bounds: e.g.,

program arr
  real, dimension(2:41) :: arr1
  real, allocatable, dimension(:), target :: arr2
  integer :: i

  allocate(arr2(40))

  forall(i = 2:41) arr1(i) = i
  arr2 = arr1 + 2

  print *, arr1(2)

  deallocate(arr2)
end program are

Running gives

$ gfortran -g foo.f90
$ gdb a.out
[...]
(gdb) break 11
Breakpoint 1 at 0x400b01: file foo.f90, line 11.
(gdb) run
[...]

Breakpoint 1, arr () at foo.f90:11
11    print *, arr1(2)
(gdb) whatis arr1
type = real(kind=4) (2:41)
(gdb) whatis arr2
type = real(kind=4) (40)

answered Oct 7, 2014 at 12:41

Jonathan Dursi

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4 Comments

Jonathan Dursi Over a year ago

I should note that the above also works with ifort, with the only difference being slightly different formatting in the output: type = REAL(4) (2:41), etc.

Konstantin Ebauer Over a year ago

Thank you a lot for your help! But what about allocatable,public arrays? I've tried whatis command in a main program with array defined as allocatable public in a called routine from a module. I've just see (,) dimension...

Jonathan Dursi Over a year ago

@KonstantinEbauer , can you give a code example? Is the array allocated yet?

user32882 Over a year ago

how can you do this with ifort? Please provide some guidance thank you...

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