Boolean operations.

The standard logical/boolean operators .EQ., .NE., .GT., .LT., .GE., .LE., .OR., .AND. and .NOT. are available and their use is identical to Fortran 77, except that there is no distinct logical data type. These boolean operators have numerical operands and return numerical values. A numerical value is considered ``true'' if it is non-zero and ``false'' if it is zero.⁷ The above operators return a value of 1 for ``true'' and zero for ``false''.

These operators may also be specified within an expression using the equivalent C forms: ==, !=, >, <, >=, <=, ||, && and !.

These operators can be used with the built-in function ``QIF''. This function has 3 arguments. It returns the value of its second argument if its first argument is non-zero (i.e. ``true''), and returns the value of its third argument otherwise. It can be used like the ``?'' operator in the C programming language.