In order to create a macro program, you must first define it. You begin a macro definition with a %MACRO statement, and you end the definition with a %MEND statement.

In the following example, the macro Printit generates a PROC PRINT step.

%macro printit;
proc print data=&syslast (obs=5);
   title "Listing of &syslast data set";
run;
%mend printit;
%printit;

In order to use the Printit macro later in your SAS programs, you must first compile it by submitting the macro definition, as follows:

%macro printit;
proc print data=&syslast (obs=5);
   title "Listing of &syslast data set";
   run;
%mend;

When you submit this code, the word scanner divides the macro into tokens and sends the tokens to the macro processor for compilation. Here is what the macro processor does:

That is, if there are no syntax errors in the macro language statements within the macro, the text between the %MACRO statement and the %MEND statement is stored under the name Printit for execution at a later time.

By default, no note is written to the log if a macro program compiles successfully. The MCOMPILENOTE= system option writes a note to the SAS log when a macro has completed compilation.

A macro might compile but still contain non-macro syntax errors. If there are any macro statement errors, an error message is written to the SAS log, in addition to the note. Here is an example of the note that is written to the log when a macro compiles without errors:

options mcompilenote=all;
%macro printit;
   proc print data=&syslast(obs=5);
      title "Listing of &syslast data set";
   run;
%mend printit;

NOTE: The macro PRINTIT completed compilation without errors.
      3 instructions 20 bytes

After the macro is successfully compiled, you can use it in your SAS programs for the duration of your SAS session without resubmitting the macro definition. Just as you must reference macro variables in order to access them in your code, you must call a macro program in order to execute it within your SAS program.

Here are the requirements for using a macro call:

To execute the macro Printit you call the macro as follows:

%printit

Suppose you have a SAS program that consists of several program steps that create SAS data sets. After each of these program steps, you want to print out the data set that has been created. Remember that the macro Printit prints the most recently created data set. If Printit has been compiled, you can call it after each step in order to print each data set.

proc sort data=sashelp.cars out=cars_mpg;
   by MPG_City;
run;
%printit                                        
proc sort data=sashelp.cars out=cars_msrp;
   by MSRP;
run;
%printit                                        

When you call a macro in your SAS program, the word scanner passes the macro call to the macro processor, because the percent sign that precedes the macro name is a macro trigger. Here is what the macro processor does when it receives %macro-name:

The macro call is processed by the macro processor before any SAS language statements such as DATA steps are compiled or executed. During macro execution, the macro processor can communicate directly with the following elements:

This example demonstrates macro execution. Assume that the Printit macro has been compiled and that it has been stored in the Work.Sasmacr catalog.

Assume that the most recently created data set is Work.Update_Schedule from an earlier example. Here is the output that is generated by calling the Printit macro.

NOTE: There were 5 observations read from the data set WORK.UPDATE_SCHEDULE.
NOTE: PROCEDURE PRINT used (Total process time):
      real time           0.02 seconds
      cpu time            0.00 seconds

Notice that in this SAS log message you see a note from PROC PRINT, but not the PROC PRINT code itself since the call to the macro does not display the text that is sent to the compiler.