specifies the fileref
assigned to the external file or directory. In a DATA step, fileref can
be a character expression, a string enclosed in quotation marks, or
a DATA step variable whose value contains the fileref. In a macro,
fileref can be any expression.
Under UNIX, fileref can
also be an environment variable. The fileref or
the environment variable that you specify must be enclosed in double
quotation marks.
Details
The FEXIST function
returns a value of 1 if the external file that is associated with fileref exists,
and a value of 0 if the file does not exist.