Backward compatibility

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Article

Created: ltomuta (08 Mar 2007)

Last edited: hamishwillee (27 Sep 2012)

Backward compatibility means compatible with earlier versions. I.e. an application built with/for version 1.0 of an SDK/system is expected to work as designed on the new version 2.0 of the same system.

Binary Compatibility

Binary compatible means that code built for an older version will run on a newer version without rebuilding.

Few examples of binary-incompatible changes:

• removing a public/protected method/member
• changing access specifiers to more restrictive
• re-ordering exported functions; new exports should be added after the old ones
• changing/adding/removing/re-ordering virtual functions
• order of data members in a class is not important, just that the sum of their size (i.e. the class size) doesn't change.

Source Compatibility

Source compatible means that the code that depends on your component can be still built without changes on a newer version of your component.

Few examples of source-incompatible changes:

• removing a public/protected method/member
• changing access specifiers to more restrictive
• changing return type of functions
• changing function arguments
• changing constness

See also

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Forward compatibility