LEN(SEXP) (INTEGER)

 Function
  Get the length of a string.

 Syntax
  LEN(str)

   str = Any string expression.

 Return Type & Value
  INTEGER
  Returns the length of a string.

 Remarks
  This function will return the length of a string.  The value returned
  will always be between 0 (an empty string) and 256 (the maximum length of
  a string).

 Examples
  STRING s
  FOPEN 1,"DATA.TXT",O_RD,S_DN
  WHILE (!FERR(1)) DO
    FGET 1,s
    PRINTLN "The length of the current string is ",LEN(s)
  ENDWHILE
  FCLOSE 1