Fortran subroutine hung up on OPEN statement

Question

I've recently started working on an existing Fortran program, and picking up the language at the same time. I wrote the following subroutine:

subroutine timing(yyyy, mm, dd, var, ntime, time_blocks, 
 *  time_day)

use myglobals

! ---------------------------------------------------------------------
!     Common Variables
! ---------------------------------------------------------------------    

    integer yyyy,       ! year
   *         mm,    ! month
   *         dd,    ! day
   *         ntime  ! nr of blocks for which time was measured

    real time_blocks(ntime),    
   *        time_day    
    character*4 var 

! ---------------------------------------------------------------------
!     Internal Variables
! ---------------------------------------------------------------------   

    integer ios
    integer out_unit=52

        open(unit=out_unit, file=diroutput(1:69)//'timing',
     * err=450, iostat=ios)
    450 print*, "iostat= ", iostat
    print*, "open"

    write(out_unit, format_str) yyyy, mm, dd, var, time_blocks, 
     *   time_day

    return
    end

The purpose of this subroutine is to write the inputs it gets from another part of the program to a file, following a defined format (format definition not included in my example). The file must be created on the first call of this subroutine, then accessed on each further call in order to append the new information. diroutput is a character string defined in myglobals.

My problem is that the program seems to get hung up at the OPEN statement, i.e. nothing happens until I kill the process. I ran the code with several print*, statements to locate the error, and found out this way that the error must be in the OPEN statement. It seems strange that the program does nothing at all, not even jump to the error label.

As I'm new to Fortran I might be missing something fairly obvious, so a quick look by someone more experienced might help. I'm certain that diroutput contains a valid path.

I'm using Linux (CentOS 5.5) and I compiled my program with Intel Fortran Compiler 11.1.

Answer 1

Your code seems, from the continuation characters in (generally) column 6, to be written in fixed-form despite containing features of Fortran 90. If it is fixed-form then statement labels, such as 450 should be in columns 1 to 5. I don't immediately see why that would cause the program to hang rather than crash, but I suggest you fix this and try again.