How does the data step statement set with point=v option works when v has a 0 or negative value?

[Steve1964]

run the following data step

data test;

p=-2;

set sashelp.class point=p;

run;

There is no error message and data step fall a dead loop!  I just wonder to where the pointer pointed   when the value of p is negative and why  no error message in log window.

[novinosrin · Accepted solution]

Hi @Steve1964   The reason for infinite loop is because when point= option random direct access is used based on observation number, SAS can't find the "End of file" marker. Therefore you would need a STOP statement to end the datastep iteration. 

Add a STOP after the set statement and take a look at the log, you should see the invalid OBS No of point=var option triggering _ERROR_ =1 .