Pragma Implementation_Defined (GNAT Reference Manual)

### 2.77 Pragma Implementation_Defined ¶

Syntax:

    pragma Implementation_Defined (local_NAME);

This pragma marks a previously declared entity as implementation-defined. For an overloaded entity, applies to the most recent homonym.

    pragma Implementation_Defined;

The form with no arguments appears anywhere within a scope, most typically a package spec, and indicates that all entities that are defined within the package spec are Implementation_Defined.

This pragma is used within the GNAT runtime library to identify implementation-defined entities introduced in language-defined units, for the purpose of implementing the No_Implementation_Identifiers restriction.