Pragma Convention_Identifier (GNAT Reference Manual)

### 2.37 Pragma Convention_Identifier ¶

Syntax:

    pragma Convention_Identifier (
             [Name =>]       IDENTIFIER,
             [Convention =>] convention_IDENTIFIER);

This pragma provides a mechanism for supplying synonyms for existing convention identifiers. The `Name` identifier can subsequently be used as a synonym for the given convention in other pragmas (including for example pragma `Import` or another `Convention_Identifier` pragma). As an example of the use of this, suppose you had legacy code which used Fortran77 as the identifier for Fortran. Then the pragma:

    pragma Convention_Identifier (Fortran77, Fortran);

would allow the use of the convention identifier `Fortran77` in subsequent code, avoiding the need to modify the sources. As another example, you could use this to parameterize convention requirements according to systems. Suppose you needed to use `Stdcall` on windows systems, and `C` on some other system, then you could define a convention identifier `Library` and use a single `Convention_Identifier` pragma to specify which convention would be used system-wide.