The KEYWORD_SET function returns a 1 (true), if its parameter is defined and nonzero; otherwise, it returns zero (false). For example, assume that a procedure is written which performs and returns the result of a computation. If the keyword PLOT is present and nonzero, the procedure also plots its result as follows:
;Procedure definition. PRO XYZ, result, PLOT = plot ;Compute result. ... ;Plot result if keyword parameter is set. IF KEYWORD_SET(PLOT) THEN PLOT, result END
A call to this procedure that produces a plot is shown in the following statement.
XYZ, R, /PLOT