Preprocessor Directives in C Language
- C Preprocessor (in short cpp) is the macro preprocessor (a separate program) which is invoked by the C Compiler before processing any other element in the program i.e. C Preprocessors are the first part of the translation during the processing (Compilation) of a C Program.
- To include the various instructions to the compiler in the C source code,some directives are used called as Preprocessor Directives.
- Each preprocessor directive have different task which executes just before the actual execution of C program which makes the program more portable.
- C Preprocessor directives are used only to instruct compilers.
- In c all the preprocessor directives start with # characterexcept define() operator.
Types of Preprocessor Directives in C Language
FILE INCLUSIVE DIRECTIVE #include MACRO SUBSTITUTION DIRECTIVE #define UNDEFINE SYMBOL DIRECTIVE #undef CONDITIONAL DIRECTIVE # if #elif #else #endif #ifdef #ifndef MISCELLANEOUS DIRECTIVE #pragma #line #error OPERATOR IN PREPROCESSOR #,##,define()
- Spaces or tabs are permitted between the # and directive name (such as inculde,define etc), but no any escape characters or other symbols are permitted. The preprocessor removes white space and concatenates the # and directive name together.
Each Preprocessor Directive would be explained in next posts of C Programming Language.