CODEWITHSUNDEEP
c++class
user768417
user768417

Reputation:

Class declarations

So I'm looking at the Ogre Character sample, and there's a class which is declared as

class _OgreSampleClassExport Sample_Character : public SdkSample

The classes identifier is Sample_Character and it is derived from the SdkSample class. What is the _OgreSampleClassExport though?

Upvotes: 0

Views: 81

Answers (2)

Captain Obvlious
Captain Obvlious

Reputation: 20063

On Windows platforms _OgreSampleClassExport is a macro used to specify the DLL linkage of a class' members. If the macro expands to __declspec(dllimport) the members exist in an external DLL and must be imported. If it expands to __declspec(dllexport) the members exist in the DLL being built and will be exported. If the macro is blank the members will be linked statically and do not exit in a DLL.

On other platforms it works in much the same way. On Linux when compiling with GCC the macro expands to __attribute__ ((visibility("???"))) where "???" specifies the linkage in a similar fashion as that used in to __declspec().

Upvotes: 3

Steven Maitlall
Steven Maitlall

Reputation: 787

This post seems relevant - Macro variable after class keyword

Essentially, it allows for the class to be exported to support a dynamically-linked library.

Upvotes: 1

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