====== Attribute names ======
===== Definitions =====
==== attribute_name ====
''[[.:bnf#prefix]] [ [[.:bnf#signature]] ] ' [[.:bnf#attribute_designator]] [ ( [[.:bnf#expression]] ) ]''

===== Examples =====
The left element of the first dimension of the one- or multi-dimensional array //register// is addressed.
<code vhdl>
register'left(1)
</code>

----

The attribute //fanout// provides the number of signals driven by //output// .
<code vhdl>
output'fanout
</code>

----

The signal //clk//, delayed by 5ns, is addressed.
<code vhdl>
clk'delayed( 5 ns )
</code>

----

By using [[.:predefined attributes]] the loop-instruction can be written in a different way as well:
<code vhdl>
FOR i IN a1'LOW TO a1'HIGH

FOR i IN a1'RIGHT TO a1'LEFT

FOR i IN a1'REVERSE_RANGE

FOR i IN a1'RANGE
</code>
<code vhdl>
SIGNAL a1: bit_vector(3 DOWNTO 0) ;
...
PROCESS (a)
   BEGIN
   z<= "0000" :
   FOR i in 0 TO 3 LOOP
      IF (a = i) THEN
         z(i) <= '1' ;
      END IF ;
   END LOOP ;
END PROCESS ;
...
</code>