If, Else and Elsif
Definition
If, Else and Elsif can be used like without Thread, but you can use Wait, While... inside and next to it.
Examples
Thread
{
If (BTN = '1')
{
LED <= '1';
}
Wait (10000);
}
Without Thread, the If would ignore procedure operations and would not wait after checking. This example checks every 10000 cycles if BTN is high and sets LED high if true.