****************************************************************************************************
*                                           PROGRAM OVERVIEW
****************************************************************************************************
*
* PROGRAM: utility_macros.sas  
* Created (mm/dd/yyyy): 03/14/2022
*
*--------------------------------------------------------------------------------------------------
* PURPOSE:
*   These are utility macros that are used to verify if a dataset contains observations.                                        
*   
*  Program inputs:                                                                                   
*                                     
*  Program outputs:                                                                                                                                       
*                                                                                                  
*  PARAMETERS:    
*   ISDATA(dataset=)
*       dataset = Name of a dataset for which we want to verify if it contains observations
*
*  Programming Notes:                                                                                
*                                                                           
*
*--------------------------------------------------------------------------------------------------
* CONTACT INFO: 
*  Sentinel Coordinating Center
*  info@sentinelsystem.org
*
*--------------------------------------------------------------------------------------------------
***********************************************************************************************;

*Macro to determine whether a dataset is empty or not;
%MACRO ISDATA(dataset=);

%PUT =====> MACRO CALLED: ms_macros v1.0 => ISDATA;

    %GLOBAL NOBS;
    %let NOBS=0;
    %if %sysfunc(exist(&dataset.))=1 and %LENGTH(&dataset.) ne 0 %then %do;
        data _null_;
        dsid=open("&dataset.");
        call symputx("NOBS",attrn(dsid,"NLOBS"));
        run;
    %end;   
%PUT &NOBS.;

%put NOTE: ********END OF MACRO: ms_macros v1.0 => ISDATA ********;

%MEND ISDATA;