Reading and Writing Text File in VHDL

Hi guys.

I have tried run this coding. But, it has error. Why it happens? Btw, i refer to this website for the tutorial. http://vhdlguru.blogspot.com/2010/03/reading-and-writing-files-in-vhdl-easy.html . Thanks in advance

--include this library for file handling in VHDL.

library std;

use std.textio.all; --include package textio.vhd

--entity declaration

entity filehandle is

end filehandle;

--architecture definition

architecture Behavioral of filehandle is

--period of clock,bit for indicating end of file.

signal clock,endoffile : bit := '0';

--data read from the file.

signal dataread : real;

--data to be saved into the output file.

signal datatosave : real;

--line number of the file read or written.

signal linenumber : integer:=1;

begin

clock <= not (clock) after 1 ns; --clock with time period 2 ns

--read process

reading :

process

file infile : text is in "1.txt"; --declare input file

variable inline : line; --line number declaration

variable dataread1 : real;

begin

wait until clock = '1' and clock'event;

if (not endfile(infile)) then --checking the "END OF FILE" is not reached.

readline(infile, inline); --reading a line from the file.

--reading the data from the line and putting it in a real type variable.

read(inline, dataread1);

dataread <= dataread1; --put the value available in variable in a signal.

else

endoffile <='1'; --set signal to tell end of file read file is reached.

end if;

end process reading;

--write process

writing :

process

file outfile : text is out "2.txt"; --declare output file

variable outline : line; --line number declaration

begin

wait until clock = '0' and clock'event;

if(endoffile='0') then --if the file end is not reached.

--write(linenumber,value(real type),justified(side),field(width),digits(natural));

write(outline, dataread, right, 16, 12);

-- write line to external file.

writeline(outfile, outline);

linenumber <= linenumber + 1;

else

null;

end if;

end process writing;

end Behavioral;