The GNU Fortran language supports construct names as defined by the Fortran 90 standard. These names are local to the program unit and are defined as follows:
construct-name: block-statement
Here, construct-name is the construct name itself;
its definition is connoted by the single colon (:); and
block-statement is an IF, DO,
or SELECT CASE statement that begins a block.
A block that is given a construct name must also specify the same construct name in its termination statement:
END block construct-name
Here, block must be IF, DO, or SELECT,
as appropriate.