neqv(3I)

NAME
     NEQV, XOR - Computes logical difference

SYNOPSIS
     NEQV ([I=]i,[J=]j)
     XOR ([I=]i,[J=]j)

STANDARDS
     Compiler extension to Fortran 95

DESCRIPTION
     NEQV and XOR are two names for the same routine.  NEQV and XOR are
     elemental functions for the CF90 compiler.

     arg and i and j can be of type Boolean, integer, real, logical, or
     Cray pointer.

CAUTIONS
     Unexpected results can occur when Boolean functions are declared
     external and then used with logical arguments.  The external Boolean
     functions always treat their arguments as type Boolean and return an
     integer result.

RETURN VALUES
     When given two arguments of type logical, NEQV and XOR compute a
     logical difference and return a logical result.  When given two
     arguments of type Boolean, integer, real, or pointer, NEQV and XOR
     compute a bit-wise logical difference and return a Boolean result.  No
     type conversion occurs.

     The following tables show both the logical difference and bit-wise
     logical difference.  NEQV is shown in the tables, but XOR produces
     identical results.

     -----------------------------------------------------------------
        Logical
      Variable 1

                       Logical
                     Variable 2

                                        (Logical Variable 1) NEQV
                                          (Logical Variable 2)

     -----------------------------------------------------------------

           T
                          T
                                                    F

           T
                          F
                                                    T

           F
                          T
                                                    T

           F
                          F
                                                    F

     -----------------------------------------------------------------

     --------------------------------------------------------------
        Bit of
      Variable 1

                      Bit of
                    Variable 2

                                      (Bit of Variable 1) NEQV
                                         (Bit of Variable 2)

     --------------------------------------------------------------

          1
                        1
                                                 0

          1
                        0
                                                 1

          0
                        1
                                                 1

          0
                        0
                                                 0

     --------------------------------------------------------------

EXAMPLES
     The following section of Fortran code shows the NEQV function used
     with two arguments of type logical.  XOR is used in the same manner
     and produces the same results.

          LOGICAL L1, L2, L3
          ...
          L3 = NEQV(L1,L2)

     The following section of Fortran code shows the NEQV function used
     with two arguments of type integer.  XOR is used in the same manner
     and produces the same results.  The bit patterns of the arguments and
     results are also given.  For clarity, only the rightmost 8 bits are
     shown.

   INTEGER I1, I2, I3
   I1 = 12
   I2 = 10
   ...
   I3 = NEQV(I1,I2)
       -------------------------------     -------------------------------
      | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 0 |   | 0 | 0 | 0 | 0 | 1 | 0 | 1 | 0 |
       -------------------------------     -------------------------------
                        I1                               I2

                     -------------------------------
                    | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 0 |
                     -------------------------------
                                       I3