A specification statement is a nonexecutable statement that declares the attributes of data objects. In Fortran 95/90, many of the attributes that can be defined in specification statements can also be optionally specified in type declaration statements.
The following are specification statements:
Explicitly specifies the properties (for example: data type, rank, and extent) of data objects.
Specifies a list of array names that are allocatable (have a deferred-shape).
Control the storage allocation of variables in subprograms.
Defines one or more contiguous areas, or blocks, of physical storage (called common blocks).
Assigns initial values to variables before program execution.
Specifies that an object is an array, and defines the shape of the array.
Specifies that a storage area is shared by two or more objects in a program unit.
Allows external (user-supplied) procedures to be used as arguments to other subprograms.
Overrides the implicit data type of names.
Specifies the intended use of a dummy argument.
Allows intrinsic procedures to be used as arguments to subprograms.
Associates a name with a list of variables. This group name can be referenced in some input/output operations.
Allows a procedure reference to omit arguments.
Defines a named constant.
Specifies that an object is a pointer.
Declare the accessibility of entities in a module.
Causes the definition and status of objects to be retained after the subprogram in which they are declared completes execution.
Specifies a pointer target.
Prevents optimizations from being performed on specified objects.
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