INCLUDEDGUARDEXAMPLEH

INCLUDEDGUARDEXAMPLEH is a conventional placeholder used in programming tutorials to demonstrate the pattern of an include guard in C and C++. An include guard is a preprocessor construct that prevents a header file from being included more than once, which can otherwise lead to redefinition errors during compilation.

A typical include guard uses a pair of preprocessor directives that enclose the entire contents of a header file. For example, a header might start with #ifndef INCLUDEDGUARDEXAMPLEH, followed by #define INCLUDEDGUARDEXAMPLEH, then the header’s declarations, and end with #endif // INCLUDEDGUARDEXAMPLEH. When the file is included again, the macro is already defined, so the preprocessor skips the file’s contents.

The macro name is usually derived from the header’s file name and written in uppercase letters to minimize conflicts with other identifiers. In real projects, developers often add a project or module prefix to further ensure uniqueness, such as MYPROJECT_INCLUDEDGUARDEXAMPLEH or a path-based variant.

While #pragma once provides a simpler, non-standardized alternative, traditional include guards remain widely used due to their portability across compilers and environments. Use of a distinctive, consistent guard name is advisable to prevent clashes in large codebases.

In practice,_INCLUDEDGUARDEXAMPLEH serves as an instructional example illustrating the mechanics of protection against multiple inclusion and the importance of careful naming to avoid macro collisions. See also include guard and #pragma once.