There are multiple problems with your macro: it expands to a statement, so you cannot use it as an expression the arguments are not properly parenthesized in the expansion: invoking this macro with anything but variable names or constants will produce problems. the arguments are evaluated multiple times: if you invoke the macro with arguments that have side effects, such …

In other words, when the compiler starts building your code, no #define statements or anything like that is left. A good way to understand what the preprocessor does to your code is to get hold of the preprocessed output and look at it.

I know that this is a long time after the original query, but this may still be useful. This can be done in GCC using the stringify operator "#", but it requires two additional stages to be defined first. #define XSTR(x) STR(x) #define STR(x) #x The value of a macro can then be displayed with: #pragma message "The value of ABC: " XSTR(ABC) See: 3.4 Stringification in the gcc online ...

Jan 24, 2024 · How do I define a preprocessor variable through CMake? The equivalent code would be #define foo.

May 14, 2011 · What is the point of #define in C++? I've only seen examples where it's used in place of a "magic number" but I don't see the point in just giving that value to a variable instead.

Oct 1, 2018 · @topher217 'dict' and 'list' are actually the class names. I believe that's to distinguish built-ins from non-built-ins as apposed to primitive vs non primitive. User-defined types are typically pascal case. Python likely derived this naming scheme from C or C++. In C structs are typically lower case (though there are a lot of people that use pascal case), and in C++ people …

Oct 28, 2009 · Is it better to use static const variables than #define preprocessor? Or does it maybe depend on the context? What are advantages/disadvantages for each method?

How do I define a function with optional arguments? Asked 13 years, 5 months ago Modified 1 year ago Viewed 1.2m times

Dec 17, 2019 · How do I declare custom exception classes in modern Python? My primary goal is to follow whatever standard other exception classes have, so that (for instance) any extra string I include in the exc...

You could for example do an ifdef guard to initialize a variable in a macro but make sure it isn't declared twice. I'm sure there are other possible use cases. Besides, it's normal to give simplified examples when asking theoretical questions. Pointing out there's a different way is kind of pointless for this kind of question.