Syntax:
pragma Unmodified (LOCAL_NAME {, LOCAL_NAME});
This pragma signals that the assignable entities (variables,
out parameters, in out parameters) whose names are listed are
deliberately not assigned in the current source unit. This
suppresses warnings about the
entities being referenced but not assigned, and in addition a warning will be
generated if one of these entities is in fact assigned in the
same unit as the pragma (or in the corresponding body, or one
of its subunits).
This is particularly useful for clearly signaling that a particular parameter is not modified, even though the spec suggests that it might be.
For the variable case, warnings are never given for unreferenced variables
whose name contains one of the substrings
DISCARD, DUMMY, IGNORE, JUNK, UNUSED in any casing. Such names
are typically to be used in cases where such warnings are expected.
Thus it is never necessary to use pragma Unmodified for such
variables, though it is harmless to do so.