Forwarddeclared

Forwarddeclared is a term used in computer programming, particularly in languages like C and C++, to describe the declaration of an identifier (such as a class, struct, enum, or function) before its full definition is provided. This declaration, often called a forward declaration, tells the compiler that the identifier exists and what its type is, but it does not provide the complete implementation details. This allows the compiler to understand references to the identifier later in the code, even if the full definition appears further down in the source file or in a different file.

The primary purpose of forward declarations is to break circular dependencies between different code modules or classes. For instance, if class A needs to refer to class B, and class B also needs to refer to class A, a direct inclusion of header files could lead to an infinite loop of inclusions. A forward declaration of one class within the header of the other can resolve this issue, allowing the code to compile.

Another benefit is improved compilation times. When a header file contains only forward declarations instead of full definitions, the compiler has less code to process. This can significantly speed up the build process, especially in large projects. However, it's important to note that a forward declaration only allows for certain operations, such as declaring pointers or references to the type. To actually use the members of the declared type or call its functions, the compiler will eventually need the full definition.