Line Segment Definition Symbol Formula Examples 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. 0 in c or c #define allows you to create preprocessor macros. in the normal c or c build process the first thing that happens is that the preprocessor runs, the preprocessor looks though the source files for preprocessor directives like #define or #include and then performs simple operations with them.

Line Segment Definition Symbol Formula Examples 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. 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?. Explicitly define datatype in python function asked 8 years, 3 months ago modified 2 years, 1 month ago viewed 101k times. The main use case for #define is for conditional compilation (where it can be very useful). you're correct that using #define for symbols and (please don't do it) macros, is not a good use case.

Line Segment Definition Symbol Formula Examples Explicitly define datatype in python function asked 8 years, 3 months ago modified 2 years, 1 month ago viewed 101k times. The main use case for #define is for conditional compilation (where it can be very useful). you're correct that using #define for symbols and (please don't do it) macros, is not a good use case. How do i define a preprocessor variable through cmake? the equivalent code would be #define foo. The #define directive is a preprocessor directive; the preprocessor replaces those macros by their body before the compiler even sees it. think of it as an automatic search and replace of your source code. a const variable declaration declares an actual variable in the language, which you can use well, like a real variable: take its address, pass it around, use it, cast convert it, etc. oh. Just do something like this: #ifdef use const #define myconst const #else #define myconst #endif then you can write code like this: myconst int x = 1; myconst char* foo = "bar"; and if you compile with use const defined (e.g., typically something duse const in the makefile or compiler options) then it will use the consts; otherwise it won't. 2 macros (created with #define) are always replaced as written, and can have double evaluation problems. inline on the other hand, is purely advisory the compiler is free to ignore it. under the c99 standard, an inline function can also have external linkage, creating a function definition which can be linked against.