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  • Ezra Schroeder thinks this is interesting:

An executable program is created for a specific hardware/system combination; it is not portable, say, from a Mac to a Windows PC. When we talk about portability of C++ programs, we usually mean portability of source code; that is, the source code can be successfully compiled and run on a variety of systems.

From

Cover of A Tour of C++

Note

by portability (definitely when talking about C++ programs) we are referring to portability of code not portability of executable, the executable is specific to a specific hardware/system