A variable assignment updates a process, procedure, or function variable with the value of an expression. The update takes effect immediately, unlike signal assignments where there is at least a delta delay before the update is reflected.

[label_name:]

variable := expression;

variable_name

Name of the variable.

expression

Expression that performs an arithmetic or logical computation by applying an operator to one or more operands.

clock <= NOT clock AFTER 10 us;

PROCESS (clock)

VARIABLE num_events : INTEGER := 0;

BEGIN

num_events := num_events + 1;

END PROCESS;