The $VARYING informat requires a length-variable that specifies the length of the variable value being read. When the length-variable is zero, the variable stores a blank value.

This is different from what the SAS® 9.2 documentation states. It states that if the value of the length-variable is zero, negative, or missing, SAS reads no data from the corresponding record.

The documentation will be changed in a future release.

Operating System and Release Information

data _null_;
  infile 'path'; 
  input @11 SYSTEM $4. @; 
  put system= ' before '; 
  LEN=0; 
  input @11 SYSTEM $VARYING4. LEN @; 
  put system= 'after '; 
run; 

SYSTEM=DDEV  before 
SYSTEM=  after 
SYSTEM=DDEV  before 
SYSTEM=  after 
SYSTEM=DDEV  before 
SYSTEM=  after 
SYSTEM=DDEV  before 
SYSTEM=  after