Syntax: @FILEEXISTS(S)
S = a string value
@FILEEXISTS returns the value 1 if file S can be opened for reading; otherwise 0.
Examples:
@FILEEXISTS(``connections.c'') = 1
@FILEEXISTS(``Q1EXPENSES91.XS'') = 1
@FILEEXISTS(``Q1EXPENSES90.WKS'') = 0