#define?
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I am having trouble understanding what #define does. I see it used a lot so I assume it is very useful but I cant wrap my head around what it does.
They are the standard way to produce include guards, and other compile-time configurations (e.g. different code paths for Windows vs. Linux), usually paired with #if clauses.
https://en.wikipedia.org/wiki/Include_guard
https://www.learncpp.com/cpp-tutorial/header-guards/
What many people in the C world do is use it to make confusing function-like macros, which I do not recommend. Macros affect everything globally and replace text before the compiler actually looks at it, and can make debugging hell.
For simple constants, use const types instead of #define. And just use functions instead of function-like macros.
https://en.wikipedia.org/wiki/Include_guard
https://www.learncpp.com/cpp-tutorial/header-guards/
What many people in the C world do is use it to make confusing function-like macros, which I do not recommend. Macros affect everything globally and replace text before the compiler actually looks at it, and can make debugging hell.
For simple constants, use const types instead of #define. And just use functions instead of function-like macros.
Last edited on
you can also use them to force inline code (one reason to use a macro function, but this should be an extremely rare thing where your over-ride of the compiler was actually better).
Personally I dislike macro functions so much that I would rather put the routine in a standalone file and #include it where it needs to be than #define macro it. They are that bad.
Personally I dislike macro functions so much that I would rather put the routine in a standalone file and #include it where it needs to be than #define macro it. They are that bad.
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