C Preprocessors?


C programming language supports preprocessors for efficient working of its program. C Preprocessor is a macro preprocessor for C based programming language. A preprocessor gives the compiler an ability for including header files, macro expansions, conditional compilation and line control in an explicit way.

The # hash tag is used to define a preprocessor i.e. all preprocessors have # in starting. Followed by the name of the preprocessor without any space in between. Here, is a list C preprocessors.

S.No.PreprocessorDescription
1.#include
Includes a specific header from the files.
2.#define
Defines a preprocessor macro.
3.#undef
Undefine a preprocessor macro
4.#if
Checks for a compile time condition and evaluates for True value.
5.#else
Evaluate as alternative of the if preprocessor.
6.#ifndef
Checks if the macros is defined. Evaluates to TRUE if not defined.
7.#elif
Combination of both #if and #else statement.
8.#error
Defines error message print by stderr method.
9.#endif
ends preprocessor condition.
10.#pragma
Used to give commands to compiler/

Updated on: 04-Oct-2019

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