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

  BLANK = blnk

  blnk  Is a character expression with one of the following
        values:

  'NULL'  Ignore all blanks in a numeric field (unless the field
          is all blanks, in which case treat blanks as zero).

  'ZERO'  Treat all blanks other than leading blanks as zeros.

  The default is 'NULL'.  However, if you specify the /NOF77 compiler
  option (or OPTIONS /NOF77), the file is implicitly opened, or the
  file is opened for internal I/O, the default is 'ZERO'.