The logical operators work on truth (Boolean) values and deliver well-formed boolean values. A non-zero value is considered true, and a zero value is considered false. All logical operators return well-formed truth values of either zero or one.

Operator Syntax Description
LNOT .LNOT. !! LNOT expression
.LNOT. expression
!! expression
Logical negation
LAND .LAND. && expression1 LAND expression2
expression1 .LAND. expression2
expression1 && expression2
Logical conjunction
LOR .LOR. || expression1 LOR expression2
expression1 .LOR. expression2
expression1 || expression2
Logical disjunction