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 …

Oct 30, 2013 · 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 …

Nov 13, 2009 · I want to use the PI constant and trigonometric functions in some C++ program. I get the trigonometric functions with include <math.h>. However, there doesn't seem to be …

May 10, 2010 · 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 …

Mar 4, 2017 · #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 …

I have been seeing code like this usually in the start of header files: #ifndef HEADERFILE_H #define HEADERFILE_H And at the end of the file is #endif What is the purpose of this?

Aug 4, 2021 · Mapped volumes can either be files/directories on the host machine (sometimes called bind mounts in the documentation) or they can be docker volumes that can be managed …

I am trying to write something like this: #define COV_ON(x) \ #ifdef COVERAGE_TOOL \ _Pragma (COVERAGE #x) #endif Is there any way to define COV_ON like this? I know what I …

How do I define a function with optional arguments? Asked 13 years, 8 months ago Modified 1 year, 3 months ago Viewed 1.2m times

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. …