The N_PARAMS function returns the number of parameters used in calling an IDL procedure or function. This function is only useful within IDL procedures or functions. User-written procedures and functions can use N_PARAMS to determine if they were called with optional parameters.
Result = N_PARAMS()
Returns the number of non-keyword parameters.
None. This function always returns the number of parameters that were used in calling the procedure or function from which N_PARAMS is called.