Delphi in a Nutshell

Name

Exports Keyword

Syntax

exports
  Subroutine,
  Subroutine name Identifier,
  Subroutine index Constant,
  Subroutine index Constant name Identifier,
  ...;

Description

The exports declaration lists the names or signatures of subroutines to be exported from a DLL. You can declare subroutines to export in any unit or in the library’s project file.

If a subroutine is overloaded, you can specify which subroutine to export by including the subroutine’s arguments in the exports declaration. You can export multiple overloaded subroutines, but make sure the caller is able to identify which one it wants to call by assigning a unique name to each one.

By default, the subroutine is exported under its own name, but you can specify a different name or an index number. If you do not supply an index, Delphi automatically assigns one.

Tips and Tricks

• You can use the index and name directives for the same exported routine (in that order).

• Delphi does not check for duplicate indices, so be careful.

• Delphi 5 does not allow the index directive for overloaded subroutines.

Example

unit Debug; interface // Simple debugging procedures. Debug messages are written to // a debug log file. You can link this unit into an application, // or use in a DLL. See the External Directive for an example // of how an application can use these procedures from a DLL. procedure Log(const Msg: string); overload; procedure Log(const Fmt: string; const Args: array of const); overload; procedure SetDebugLog(const FileName: string); function ...