Tries to count nobs by metadata, else default to recusion count.

nobs.sas

%macro nobs(data=_last_);
	%local dsid anobs whstmt counted rc;
	%let DSID = %sysfunc(open(&DATA., IS));

	%if &DSID = 0 %then %do;
		%put %sysfunc(sysmsg());
		%let counted = .;
		%goto mexit;
	%end;
	%else %do;
		%let anobs  = %sysfunc(attrn(&DSID, ANOBS));
	%end;

	%if &anobs=1 %then
		%let counted = %sysfunc(attrn(&DSID, NLOBS));
	%else %do;
		%put INFO: Observations in "&DATA." must be counted by iteration.;
		%let counted = 0;

		%do %while (%sysfunc(fetch(&DSID)) = 0);
			%let counted = %eval(&counted. + 1);
		%end;
	%end;

	%let rc = %sysfunc(close(&DSID));
%MEXIT:
	&COUNTED. 
%mend nobs;