Define stable population. Jun 18, 2012 · #define WIDTH 10 is a preprocessor directive that allows you to specify a name (WIDTH) and its replacement text (10). 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. 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". 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. 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). The compiler never actually sees a macro name at all, what it sees is the replaced text. When referencing variables The #define directive is a preprocessor directive; the preprocessor replaces those macros by their body before the compiler even sees it. You are passing a variable to a template, which is fine. Manually delete everything that is not a source file, project file or resource and build again. You're correct that using #define for symbols and (please don't do it) macros, is not a good use-case. 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). 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?. Oh May 10, 2010 · 0 in C or C++ #define allows you to create preprocessor Macros. #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. Think of it as an automatic search and replace of your source code. I know that this is a long time after the original query, but this may still be useful. What's reputation and how do I get it? Instead, you can save this post to reference later. Jun 18, 2012 · #define WIDTH 10 is a preprocessor directive that allows you to specify a name (WIDTH) and its replacement text (10). Mar 4, 2017 · #define simply substitutes a name with its value. 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. You'll need to complete a few actions and gain 15 reputation points before being able to upvote. Upvoting indicates when questions and answers are useful. This can be done in GCC using the stringify operator "#", but it requires two additional stages to be defined first. A condition is a runtime expression. Oh Mar 4, 2017 · #define simply substitutes a name with its value. 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. Here’s how you can use it, but lots to unpack to understand why. The preprocessor parses the source file and each occurrence of the name is replaced by its associated text. (# is not an allowed character in #define). If it is set there, this sounds like a stale preprocessed header thing. 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. Feb 15, 2025 · Revising my answer based on the updated question. 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. Oct 30, 2013 · The main use-case for #define is for conditional compilation (where it can be very useful). 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. Jan 24, 2024 · How do I define a preprocessor variable through CMake? The equivalent code would be #define foo. The following statements are equivalent: condition: succeeded() # equivalent to: condition: $[ succeeded() ] Variables are also only evaluated at runtime. e8y4 py3su37 zsyxt gi tid4 m6aerpe erim2h ud hxbdu xm8sc