vlt.file.addline

  ADDLINE - add a line of text to a text file

  [B, ERRORMSG] = ADDLINE(FILENAME, MESSAGE)

  ADDLINE writes a message to the textfile FILENAME. If the FILENAME does not exist, then ADDLINE
  attempts to create it. ADDLINE first attempts to check out a lock file so that two programs do not write to the
  FILENAME simultaneously. 

  A newline '\n' and carriage return '\r' is added to the end of the message.

  If the operation is successful, B is 1 and ERRORMSG is ''. Otherwise, B is 0 and ERRORMSG describes the error.