eqv(3M)

NAME
     EQV - Computes logical equivalence

SYNOPSIS
     EQV ([I=]i,[J=]j)

IMPLEMENTATION
     UNICOS, UNICOS/mk, and IRIX systems

STANDARDS
     Compiler extension to Fortran 90

DESCRIPTION
     EQV is an elemental function for the CF90 compiler.

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

NOTES
     EQV is an outmoded routine for the CF90 compiler.  Refer to the
     Fortran Language Reference Manual, Volume 3, publication SR-3905, for
     information about outmoded features and their preferred standard
     alternatives.

     The name of this intrinsic cannot be passed as an argument.

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 a
     Boolean result.  When given two arguments of type logical, EQV
     computes a logical equivalence and returns a logical result on UNICOS
     and UNICOS/mk systems.  On IRIX systems, they return an integer
     result.

RETURN VALUES
     When given two arguments of type Boolean, real, integer, or pointer,
     EQV computes a bit-wise logical equivalence and returns a Boolean
     result.  No type conversion occurs.

     The following tables show both the logical equivalence and bit-wise
     logical equivalence:

     -----------------------------------------------------------------
        Logical        Logical          (Logical Variable 1) EQV
      Variable 1     Variable 2           (Logical Variable 2)
     -----------------------------------------------------------------
           T              T                         T
           T              F                         F
           F              T                         F
           F              F                         T
     -----------------------------------------------------------------


     --------------------------------------------------------------
        Bit of        Bit of           (Bit of Variable 1) EQV
      Variable 1    Variable 2           (Bit of Variable 2)
     --------------------------------------------------------------
          1             1                        1
          1             0                        0
          0             1                        0
          0             0                        1
     --------------------------------------------------------------

EXAMPLES
     The following section of Fortran code shows the EQV function used with
     two arguments of type logical:

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

     The following section of Fortran code shows the EQV function used with
     two arguments of type integer.  The bit patterns of the arguments and
     result are also given.  For clarity, only the rightmost 8 bits are
     shown.

INTEGER I1, I2, I3
I1 = 12
I2 = 10
...
I3 = EQV(I1,I2)

       -------------------------------     -------------------------------
      | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 0 |   | 0 | 0 | 0 | 0 | 1 | 0 | 1 | 0 |
       -------------------------------     -------------------------------
                    I1                              I2

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

SEE ALSO
     Intrinsic Procedures Reference Manual, publication SR-2138, for the
     printed version of this man page.