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

  Executes the statement at the first label if the arithmetic
  expression evaluates to a value less than 0; the statement at the
  second label if the arithmetic expression evaluates to 0; or the
  statement at the third label if the arithmetic expression evaluates
  to a value greater than 0.  Statement format:

     IF (e) s1,s2,s3

     e         Is an arithmetic expression.

     s1,s2,s3  Are labels of executable statements in the same
               program unit.  All three labels are required,
               but they need not refer to different statements.

  Executes the statement at the first label ("s1") if the arithmetic
  expression evaluates to a value less than 0; the statement at the
  second label ("s2") if the arithmetic expression evaluates to 0; or
  the statement at the third label ("s3") if the arithmetic
  expression evaluates to a value greater than 0.