VHDL "EVENT" Problem

[Altera_Forum]

Hello, I'm a beginner for using Quartus II. I have an error in this VHDL code 

-------------------------------------------------------------------------------------- library ieee; use ieee.std_logic_1164.all; use ieee.numeric_std.all;   entity Test is  port(clk : in std_logic;  preset : in std_logic;  flag : in std_logic;   out : out std_logic_vector(15 downto 0);  done : out std_logic    ); end Test;   architecture RTL of Test is  signal d :std_logic_vector(15 downto 0);  signal q :std_logic_vector(15 downto 0);  signal I :std_logic_vector(15 downto 0) := "0111010101001101";  signal flag_sgl : std_logic ;  signal done_sgl, VI, : std_logic;   begin  process(clk,flag)    begin    if(preset= '0') then   flag_sgl <= '0';  done_sgl <= '0';  VI <= '1';  elsif (clk'event and clk='1') then   VI <= '0';    if (flag_sgl = '1')then   flag_sgl <= '0';  done <= not(done_sgl);  done_sgl <= not(done_sgl);  out <= q(15 downto 0);  q <= d;    end if;  end if;    if (flag'event ) then  flag_sgl <= '1';  end if;  end process ;   ------------------------ d(0) <= I(0) when VI = '1' else q(1) ; d(1) <= I(1) when VI = '1' else q(2) ; d(2) <= I(2) when VI = '1' else q(0) xor q(3) ; d(3) <= I(3) when VI = '1' else q(4) ; d(4) <= I(4) when VI = '1' else q(5) ; d(5) <= I(5) when VI = '1' else q(6) ; d(6) <= I(6) when VI = '1' else q(0) xor q(7) ; d(7) <= I(7) when VI = '1' else q(8) ; d(8) <= I(8) when VI = '1' else q(9) ; d(9) <= I(9) when VI = '1' else q(0) xor q(10); d(10) <= I(10) when VI = '1' else q(11) ; d(11) <= I(11) when VI = '1' else q(0) xor q(12); d(12) <= I(12) when VI = '1' else q(13) ; d(13) <= I(13) when VI = '1' else q(14); d(14) <= I(14) when VI = '1' else q(0) xor q(15); d(15) <= I(15) when VI = '1' else q(0);   end architecture RTL; ----------------------------------------------------------------------------------------- I got a problem in the "RED" color line. I would like "flag_sgl" change value to '1', everytime that input signal "flag" change its value. Are there any way for detecting "flag" changing without using 'EVENT? Thank you in advance ^^

[Altera_Forum]

Using edge like that translates to clock port signal with its rules. Better detect change of value: 

 inside process flag_d <= flag; if flag /= flag_d then ... end if;

[Altera_Forum]

process(preset, clk)