Logical

A logical expression (logical_expr), when evaluated, produces a result of type logical. The form of a logical expression is:


>>-+-----------------------------+--logical_disjunct-----------><
   '-logical_expr--+-.EQV.-----+-'                     
                   +-.NEQV.----+                       
                   |       (1) |                       
                   '-.XOR.-----'

Notes:

XL Fortran logical operator

The form of a logical_disjunct is:


>>-+------------------------+--logical_term--------------------><
   '-logical_disjunct--.OR.-'

The form of a logical_term is:


>>-+---------------------+--logical_factor---------------------><
   '-logical_term--.AND.-'

The form of a logical_factor is:


>>-+--------------------------------+--------------------------><
   '-+-------+--+-logical_primary-+-'   
     '-.NOT.-'  '-rel_expr--------'

logical_primary is a primary of type logical.

rel_expr is a relational expression.

The logical operators are:

Logical Operator	Representing	Precedence
.NOT.	Logical negation	First (highest)
.AND.	Logical conjunction	Second
.OR.	Logical inclusive disjunction	Third
.XOR. 1	Logical exclusive disjunction	Fourth (lowest)
.EQV.	Logical equivalence	Fourth (lowest)
.NEQV.	Logical nonequivalence	Fourth (lowest)

Note:

XL Fortran logical operator.

IBM extension begins The .XOR. operator is treated as an intrinsic operator only when the -qxlf77=intxor compiler option is specified. (See the -qxlf77 option in the XL Fortran Compiler Reference for details.) Otherwise, it is treated as a defined operator. If it is treated as an intrinsic operator, it can also be extended by a generic interface. IBM extension ends

The precedence of the operators determines the order of evaluation when a logical expression containing two or more operators having different precedences is evaluated. For example, evaluation of the expression A.OR.B.AND.C is the same as evaluation of the expression A.OR.(B.AND.C).

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