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- c++ - What does ## in a #define mean? - Stack Overflow
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
- How can I use #if inside #define in the C preprocessor?
How can I use #if inside #define in the C preprocessor? Asked 15 years, 6 months ago Modified 8 months ago Viewed 51k times
- Is it possible to use a if statement inside #define?
As far as I know, what you're trying to do (use if statement and then return a value from a macro) isn't possible in ISO C but it is somewhat possible with statement expressions (GNU extension) Since #define s are essentially just fancy text find-and-replace, you have to be really careful about how they're expanded I've found that this works on gcc and clang by default:
- c# - How do you use #define? - Stack Overflow
8 #define is used to define compile-time constants that you can use with #if to include or exclude bits of code
- What is the difference between #define and const? [duplicate]
The difference is that #define is processed by the preprocessor doing what amounts to simple text replacement Const values defined like this are not visible for the actual compiler, while a variable defined with the const modifier is an actual typed "variable" (well not really that variable) The disadvantage of #define is that is replaces every occurence of the name, while const variables
- Why do most C developers use define instead of const?
#define simply substitutes a name with its value Furthermore, a #define 'd constant may be used in the preprocessor: you can use it with #ifdef to do conditional compilation based on its value, or use the stringizing operator # to get a string with its value
- Difference between `constexpr` and `#define` - Stack Overflow
So I read the interesting answers about what are the differences between constexpr and const but I was curious about are the differences between #define and constexpr ? I feel like constexpr is jus
- What is the purpose of the #define directive in C++?
#define to define numerical constants can be easily replaced by a const "variable", that, as a #define, doesn't really exist in the compiled executable AFAIK it can be used in almost all the situations where you could use a #defined numerical constant, including array bounds
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