Header Files

A header file is a file containing C declarations and macro definitions (see section Macros) to be shared between several source files. You request the use of a header file in your program with the C preprocessing directive `#include'.

• Header Uses: What header files are used for.
• Include Syntax: How to write `#include' directives.
• Include Operation: What `#include' does.
• Once-Only: Preventing multiple inclusion of one header file.
• Inheritance: Including one header file in another header file.