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How and Why to Avoid Preprocessor Macros

While most naming conflicts in C++ can be solved using namespaces), this is not true for preprocessor macros.

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How and Why to Avoid Preprocessor Macros

Macros can not be put into namespaces. If you would try to declare a new class called Stream, but somewhere in a header you include would be a macro called Stream, things would break. While compiling your code, the preprocessor would simply replace the Stream in your class Stream { declaration. You could get a really confusing error message, and it would take time and energy to find the actual problem.

Especially people developing software for controllers, often overuse macros for almost everything. They believe it will save RAM, speed up the code or make it more flexible. Often none of these three things are true. Actually each additional macro is a risk for name conflicts and makes the code less readable. You should reduce the use of macros to the absolute minimum, and especially avoid macros in your header files.

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