The C preprocessor
*
The C Preprocessor is a separate step in the compilation process, but not part
of the compiler.
The
C preprocessor.
- All preprocessor lines always begin with #.
The unconditional directives are as follows:
- #define – Define a preprocessor macro
- #include – Insert a particular header from another file
- #undef – Undefine a preprocessor macro
The conditional directives are as follows:
- #ifndef – If this macro is not defined
- #ifdef – If this macro is defined
- #if – Test if a compile time condition is true
- #elif – #else an #if in one statement
- #else – The alternative for #if
- #endif – End preprocessor conditional
