Logical variables and constants
LOGICAL constant is either
False. The Fortran standard
does not specify how variables of
LOGICAL type are represented.
However, it does require
LOGICAL variables of default kind to have
the same storage size as default
For Arm® Fortran Compiler:
.TRUE.corresponds to -1 and has a default storage size of 4-bytes.
.FALSE.corresponds to 0 and has a default storage size of 4-bytes.
Some compilers represent
.FALSE. as 1 and 0, respectively.