/sys$common/syshlp/helplib.hlb FORTRAN, /WARNINGS, TRUNCATED_SOURCE  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  Controls whether the compiler issues a warning diagnostic message
  (EXCCHASRC) when it reads a source line with a statement field that
  exceeds the maximum column width.  The maximum column width is
  either 72 or 132 characters, depending on the value of the
  /EXTEND_SOURCE qualifier or the OPTIONS statement qualifier in
  effect.

  This option has no effect on truncation; lines that exceed the
  maximum column width are always truncated.