A macro is a single mnemonic that stands for a control code or a sequence of control codes. There are also some reasons we should not use the C++ macros with the #define, such as No scoping, No type checking, No access control, and No symbol.If you use a C99 or later compiler #define debug_print(fmt. This section of a PDF contains user-defined macros.It can be called by () character followed by the macro name. Once the macro is defined, it can be used anywhere in a compilation unit scope, wherever required. The directive define creates a macro for substitution code. The various preprocessor functions are #include, #define, #undef, #ifdef, etc. The term ‘macro’ refers to the substitution of a line or a few lines of text code.Most compilers do not include macros in their debugging information, even when. You may need to compile your program specially to provide GDB with information about preprocessor macros. A multi-line macro contains more than one line of macros in it. GDB can evaluate expressions containing macro invocations, show the result of macro expansion, and show a macro’s definition, including where it was defined.The function-like macro is almost similar to the function call in a program.The object-like macro in C++ Macros is an identifier that gets replaced by code fragments.The chain macros in C++ Macros are defined as macros inside the macros.The various types of C++ macros are Chain macros, Object-like macros, Function-like macros, and Multi-line macros.A C++ macro is defined as a section of code that can be replaced by that particular macro value.Macro definitions need not be terminated by a semi-colon ( ). Whenever a macro name is encountered by the compiler, it replaces the name with the definition of the macro. To learn more about Preprocessor directives in C++, click here- Preprocessor Directives in C++ Conclusion The utils macros define the infrastructure needed to enable the object/component for correct factory operation. A macro is a piece of code in a program that is replaced by the value of the macro. You generally use this syntax when creating constants that. When we can only see the value of the constant and not the name, debugging is difficult. Macro definitions are not variables and cannot be changed by your program code like variables. The compiler never sees the name as a result and cannot add it to the symbol table. No symbol: The preprocessor may remove the symbolic name from our code. No access control: We do not have any control over the #define. No scoping: A constant that is defined in the #define is global. So we must need to specify that type of constant. When the macro is defined, the preprocessor includes the corresponding code up to the closing endif command. No type checking: We can not type check the constant we define using the #define. Each expands to a character string literal containing a conversion specifier which can be modified by a. Macro definitions are not variables and cannot be changed by your program code like variables. These macro definitions allow constant values to be declared for use throughout your code. There are various reasons we should not use the #define for constants in C++. The following macros are defined in inttypes.h. In the C Programming Language, the define directive allows the definition of macros within your source code. The PI gets represented every time the user calls it. In the above example, we are getting the value of PI by defining a macro PI and its value which is 3.14159.
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