Define i2 statistic. #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. The preprocessor parses the source file and each occurrence of the name is replaced by its associated text. Mar 4, 2017 · #define simply substitutes a name with its value. So is there any solution? The #define directive is a preprocessor directive; the preprocessor replaces those macros by their body before the compiler even sees it. A condition is a runtime expression. . 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. Oh May 10, 2010 · 0 in C or C++ #define allows you to create preprocessor Macros. Jun 18, 2012 · #define WIDTH 10 is a preprocessor directive that allows you to specify a name (WIDTH) and its replacement text (10). Upvoting indicates when questions and answers are useful. 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. 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. The compiler never actually sees a macro name at all, what it sees is the replaced text. You are passing a variable to a template, which is fine. 2m times 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 have done above is wrong as I can't have #ifdef inside #define. Manually delete everything that is not a source file, project file or resource and build again. 4 Stringification in the gcc online Jul 30, 2014 · Check what Michael said: in the build log, is there a _AFXDLL? Do not define it manually, it is added when you set "Use MFC in a shared DLL". Oh Mar 4, 2017 · #define simply substitutes a name with its value. Oct 30, 2013 · The main use-case for #define is for conditional compilation (where it can be very useful). You'll need to complete a few actions and gain 15 reputation points before being able to upvote. 2m times 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? Jun 18, 2012 · #define WIDTH 10 is a preprocessor directive that allows you to specify a name (WIDTH) and its replacement text (10). This can be done in GCC using the stringify operator "#", but it requires two additional stages to be defined first. 2m times 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? Oct 30, 2013 · The main use-case for #define is for conditional compilation (where it can be very useful). (# is not an allowed character in #define). Here’s how you can use it, but lots to unpack to understand why. I know that this is a long time after the original query, but this may still be useful. Oct 30, 2013 · The main use-case for #define is for conditional compilation (where it can be very useful). Feb 15, 2025 · Revising my answer based on the updated question. When referencing variables The #define directive is a preprocessor directive; the preprocessor replaces those macros by their body before the compiler even sees it. Nov 4, 2009 · Which one is better to use among the below statements in C? static const int var = 5; or #define var 5 or enum { var = 5 }; How do I define a function with optional arguments? Asked 13 years, 8 months ago Modified 1 year, 4 months ago Viewed 1. Jan 24, 2024 · How do I define a preprocessor variable through CMake? The equivalent code would be #define foo. What's reputation and how do I get it? Instead, you can save this post to reference later. If it is set there, this sounds like a stale preprocessed header thing. The following statements are equivalent: condition: succeeded() # equivalent to: condition: $[ succeeded() ] Variables are also only evaluated at runtime. You're correct that using #define for symbols and (please don't do it) macros, is not a good use-case. Think of it as an automatic search and replace of your source code. 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? What is define ( [ , function ]) in JavaScript? [duplicate] Asked 12 years, 5 months ago Modified 2 years, 10 months ago Viewed 240k times How do I define a function with optional arguments? Asked 13 years, 8 months ago Modified 1 year, 4 months ago Viewed 1. gdl8nf 301 4gjy lypi1h xojrkp r5v odh4u5 g7a0 faej ss