In expansion of macro in c code#

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. This gives the macro some of the power of a function. Note: M_PI is also a macro inside math.h library file. C:UsersJonathanDocumentsArduinolibrariesMFRC522srcMFRC522.cpp:1283:31: note: in expansion of macro F case STATUSERROR: return F(Error in. A parameterized macro is a macro that is able to insert given objects into its expansion. You can view EDUCBA’s recommended articles for more information. We hope that this EDUCBA information on Macros in C was beneficial to you.

In expansion of macro in c code#

This is very useful to save time and have less code writing. Using M_PI constant present in Math.h header file #include The macro uses the define directive to define the macro in the C programming language. With this simple example I’m trying to illustrate that we can make use of Macro template inside macro expansion of another macro definition. The ‘define’ directive is used to define a macro. Whenever this name is encountered by the compiler, the compiler replaces the name with the actual piece of code. Prefer inline or static functions to function-like macros and PRE02-C. Macros In C/C++, Macros are pieces of code in a program that is given some name. In above source code, preprocessor replaces every occurrence of PI with 3.14159265358979323846 and then checks for every occurrence of AREA(r) and replaces with ( 3.14159265358979323846 * r * r ). Parenthesize all parameter names in macro definitions. The process of replacing a macro call with the processed copy of the body is called expansion of the macro call.

If the macro accepts arguments, the actual arguments following the macro name are substituted for formal parameters in the macro body. the arguments are evaluated multiple times: if you invoke the macro with arguments that have side effects, such as SUMA(a(), b()) or SUMA(p++, 2), the side effect will occur multiple times. The macro name is replaced by a copy of the macro body. The text replacement, combined with a poor integration with C++ features, make a dangerous mix.

Printf('Area of Circle is %f ', AREA(r)) the arguments are not properly parenthesized in the expansion: invoking this macro with anything but variable names or constants will produce problems. The expanded version of the macro is then: int x 42 int y 43 int z (++x < ++y) ++y : ++x std::cout << x << ' ' << y << ' ' << z << ' ' The bigger value, here y, gets incremented twice. YouTube Link: Source Code: Using Macro Template In Macro Expansion: C Program #include