File I/O problem. VHDL

I am trying to write information to a text file in VHDL. Here is my code



type frame_data is array (31 downto 0) of std_logic_vector(31 downto 0);



type my_file is file of frame_data;
file load_file : my_file is out "DSP_Output.txt";

variable trace_line : line;



write ( trace_line,string'("test"));
writeline (load_file,trace_line);


I recieve the following error when i check syntax:



writeline can not have such operands in this context.

mreister