# Logical Constants

A logical constant represents only the logical values true or false, and takes one of the following forms:

.TRUE.[_k]

.FALSE.[_k]

k | Is the optional kind parameter: 1 for LOGICAL(1), 2 for LOGICAL(2), 4 for LOGICAL(4), or 8 for LOGICAL(8). It must be preceded by an underscore ( _ ).

The numeric value of .TRUE. and .FALSE. can be -1 and 0 or 1 and 0 depending on compiler option fpscomp [no]logicals. Logical data can take on integer data values. Logical data type ranges correspond to their comparable integer data type ranges. For example, the LOGICAL(2) range is the same as the INTEGER(2) range.

Parent topic: Logical Data Types