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The ability to use a familiar procedural language as the macro language gives power much greater than that of text substitution macros, at the expense of a larger and slower compiler. Macros in PL/I, as well as in many assemblers, may have side effects, e.g., setting variables that other macros can access.
A variadic macro is a feature of some computer programming languages, especially the C preprocessor, whereby a macro may be declared to accept a varying number of arguments. Variable-argument macros were introduced in 1999 in the ISO/IEC 9899:1999 ( C99 ) revision of the C language standard, and in 2011 in ISO/IEC 14882:2011 ( C++11 ) revision ...
Many compilers define additional, non-standard macros. A common reference for these macros is the Pre-defined C/C++ Compiler Macros project, which lists "various pre-defined compiler macros that can be used to identify standards, compilers, operating systems, hardware architectures, and even basic run-time libraries at compile-time."
The C preprocessor does not expect its input to use the syntax of the C language. Some languages take a different approach and use built-in language features to achieve similar things. For example: Instead of macros, some languages use aggressive inlining and templates.
In computing, inline expansion, or inlining, is a manual or compiler optimization that replaces a function call site with the body of the called function. Inline expansion is similar to macro expansion, but occurs during compilation, without changing the source code (the text), while macro expansion occurs prior to compilation, and results in different text that is then processed by the compiler.
In ISO C, each obstack function has both a macro definition and a function definition. The function definition is used if the macro substitution fails. An ordinary call uses the macro definition by default, but you can request the function definition instead by writing the function name in parentheses, as shown here:
m4 is a general-purpose macro processor included in most Unix-like operating systems, and is a component of the POSIX standard.. The language was designed by Brian Kernighan and Dennis Ritchie for the original versions of UNIX.
IAL provides macro-substitution with the do-statement; this was dropped in ALGOL 60. IAL allows one or more array subscripts to be omitted when passing arrays to procedures, and to provide any or all arguments to a procedure passed to another procedure. IAL's infix Boolean operators are all of the same precedence level.