Miscellaneous (GNAT Reference Manual)

#### 7.1.5 Miscellaneous ¶

- `Scalar_Storage_Order` attribute applies to ‘generic types’ (normally it does not).
- Only the `--!` special comment sequence is recognized; all others are disallowed.
- The `Priority` aspect/attribute on protected types accepts the unconstrained type `Any_Priority` rather than the subtype `System.Priority` (a subrange of `Integer`), giving GNAT’s own protected objects access to the full implementation-defined priority range.
- `pragma Extend_System` is ‘ignored’ (prevents circularities in System). Exception: predefined renaming units (`Text_IO`, `Direct_IO`, etc.) are compiled without GNAT implementation mode so that `Extend_System` still works for them.
- Importing a non-pure external function (`pragma Import`) into a `Pure` unit does ‘not’ produce a purity warning, on the assumption that the runtime knows the purity properties of the C functions it imports.
- `pragma Style_Checks ("All_Checks")` activates the stricter `-gnatyg` rule set rather than the default `-gnaty` set.