When debugging a FORTRAN program step by step, if the debugger gets into the execution of a statement expanding more than one line, the "step" command is stuck between the lines of the multi-line statement about ~18 cycles before it exits and continues to the next statement. For instance assume the following FORTRAN code that expands into two lines:
Line 1: ep_data(order(i))%EE = (ep_data(order(i))%landings + m_consumed(order(i))) &
Line 2: / (ep_data(order(i))%PoB * ep_data(order(i))%biomass)
Line 3: group_no = count(detritus_group_no(:) < order(i)) + 1
When the debugger gets into the execution of the first line (Line 1) of the statement, you can "step" to the next part of the statement on the second line (Line 2). Once you are on the second line, if you issue "step" one more time, the debugger prompt goes back to the previous line (Line 1). The debugger is held stuck between these two lines for about ~18 cycles until it breaks the cycle and proceeds to the following statement on Line 3.
I would be glad if you have an idea about this strange problem and could share the solution with me.