Search results
Results from the WOW.Com Content Network
The __VA_OPT__ macro is replaced by its argument when arguments are present, and omitted otherwise. Common compilers also permit passing zero arguments before this addition, however. [4] [6] The C preprocessor rules prevent macro names in the argument of __VA_OPT__ from expanding recursively. It is possible to work around this limitation up to ...
The distinguishing features of this style of macro preprocessing included: free-form syntax (not line-based like a typical macro preprocessor designed for assembly-language processing) the high degree of re-expansion (a macro's arguments get expanded twice: once during scanning and once at interpretation time)
The C preprocessor (CPP) is a text file processor that is used with C, C++ and other programming tools. The preprocessor provides for file inclusion (often header files), macro expansion, conditional compilation, and line control. Although named in association with C and used with C, the preprocessor capabilities are not inherently tied to the ...
For #include guards to work properly, each guard must test and conditionally set a different preprocessor macro. Therefore, a project using #include guards must work out a coherent naming scheme for its include guards, and make sure its scheme doesn't conflict with that of any third-party headers it uses, or with the names of any globally visible macros.
The ISO C specification makes allowance for these keywords as preprocessor macros in the header file iso646.h. For compatibility with C, C++ also provides the header iso646.h, the inclusion of which has no effect. Until C++20, it also provided the corresponding header ciso646 which had no effect as well.
Note that the preprocessor is in principle language agnostic, and is a lexical preprocessor, working at the lexical analysis level – it does not do parsing, and thus is unable to do any processing specific to C syntax. The input to the compiler is the translation unit, and thus it does not see any preprocessor directives, which have all been ...
A parameterized macro is a macro that is able to insert given objects into its expansion. This gives the macro some of the power of a function. As a simple example, in the C programming language, this is a typical macro that is not a parameterized macro, i.e., a parameterless macro: #define PI 3.14159
A general-purpose macro processor or general purpose preprocessor is a macro processor that is not tied to or integrated with a particular language or piece of software.. A macro processor is a program that copies a stream of text from one place to another, making a systematic set of replacements as it does so.